Let me put it another way. Based on the system I'm suggesting. Single player mode. You crash on the beach. You have 0 Camp Supplies. You find fish and other food equalling roughly 15 camping supplies. You meet SH. You fight intellect devourers. You're new to the game, so you stink at combat, and they nearly kill both of your characters. You REALLY need to long rest. Forget short. You're hurting bad and used up all your spells.
You're stressing. You found 15 camping supplies and it's just you and SH. That's only 4 camping supplies to short rest. 20 to long rest. Dang! Do you ask SH to leave the party so you can LR? But then, you're traveling by yourself. Or, do you trust you'll be okay as long as you SR right now for 4 and hope you find enough soon to LR? You do this, SRing for now and using an HP Recovery (you should get two at this point because of level up to level 2). Either way, you should have at least 1 to spend for now.
You could either now go through the nautiloid or outside beyond. Wisdom would say, "Hey. You found food on the beach. Maybe you'll find more food on that side too where there's a shore." So, going out, you find more food. Ah! Enough for an LR. Now you're feeling better, but it's still kinda limiting you. You've only got just enough for an LR. You decide to do it.
SH says, "I'm not sure this is such a good idea. We could turn into mind flayers at any moment. We need to find a healer." She then tries to prompt you, per the dialogue that you trigger if you LR at this point, that you shouldn't really be doing this right now. In other words, Larian is telling the player to trust the DM and keep going. Don't rest here. Then have the game give you the option to back out and not actually LR at this point. Return to where you were and keep going OR keep going through with the LR and pray for the best. Either way, you have more options with this approach.
But then - I'm not done yet - as you keep going, regardless of which path you chose - either through the nautiloid or go outside and find more food - you are able to keep going because an SR should be enough for you to heal up to face a few fishermen, especially since all you have to do is be smart enough to shoot the mind flayer to get them to stop trying to kill you - and this only IF you fail to convince them to not attack you.
OR... you face Astarion... or both... Whatever the case, with food supplies so sparse, do you add him to your party or no? Maybe you aren't comfortable doing so because you don't have a lot of food and the tool tips explained to you (assuming they would) that if you add more party members the food cost goes up for both types of rests. Ah! But isn't there bound to be more food around? Wait! didn't Astarion just chase a boar into some bushes? FOOOD!
See? MORE options. More value for each type of rest. Short resting can keep you going for less food cost. You might even push yourself a bit more than you would normally if you didn't have the cost associated with the rests. After all, no cost at all would mean, "Why not?" Food cost now says, "Well, maybe you won't have enough for later. Maybe you should weigh your options."
"But this is early game," you might say. "This is pointless for later when you can go to vendors."
Nope. Why? I found 320 camping supplies worth of food and supply packs, etc. on my quest from the beach to the grove. I find out that each vendor sells camp supply packs worth 40 camping supplies each. They are worth (let's just say) 30 gp each pack. I now have all 5 origin characters in the party. That's 60 camping supplies per long rest and (with a party of 4) only 8 camping supplies per short rest.
Now, I CAN long rest at least 5 times and even still short rest for 2 with the amount of camping supplies I have between my party inventory and what's at camp. I'm sure to find even more as I continue. But, do I really have a guarantee that I'll find more? Nope. There's no guarantee that I'll ever find more. Sure. In later playthroughs I'll get a sense of just how much I'll find, but in the initial playthrough, I won't know.
And even if I DO know, so what? The cost of a long rest is still WAY bigger than short rest. I'm still not going to just long rest between every fight because that 320 camping supplies will go real fast if I do. Think about it. I fight the owlbears. 60 camping supplies. I fight the goblins at the entrance to the village. 60 camping supplies. I fight more goblins. 60 camping supplies. I fight the ogres. 60 camping supplies. I fight more goblins and a bugbear and ogre female. 60 camping supplies. I fight the ettercaps. 60 camping supplies. I fight phase spiders. 60 camping supplies. Etc. etc. etc.
Even IF I find another 60 camping supplies just in Moonhaven, spamming long rest is dropping my overall supplies dangerously low. Yes. I sure can just go to the vendor and drop 30 gp for another supply pack, but again. Why? Why would I want to do that if I can help it? Wouldn't it be wiser to NOT long rest so much and maybe keep some stores of camping supplies at camp in case I do have some bad RNG going on?
And then, on top of that, IF Larian made it so there are areas where you find less food - like the Underdark or Grymforge (have you noticed you don't find as much food in those areas?), then having those lots and lots of extra stores of food that you found on the surface is intelligent gameplay.
And THEN, even IF you unwisely spent all your food supplies spamming long rest constantly between every single fight in the game, all you'd need to do is go to a vendor to buy more so you don't get soft locked.
So, yes. It still works. Why? It discourages you from long resting in some fashion while still leaving plenty of room for players to long rest a lot if they need/want to.
Again, it's putting the gameplay into the hands of the player while mentally encouraging the use of both types of rest. Current gameplay simply encourages long rest and makes short rest only a quality of life quick heal button. That's SRs only current purpose. It has no other real strategic meaning or purpose.
