THAT is why you have other members in a party. It's TEAM-based.
Now, now ... i never said that is single character, that is once again your own interpretation. :P
The situation could be just the same if you fight at least semi-inteligent creatures, who understands that keep attacking that armored dude in front, while the second dude keeps healing him will probably not work well ... and some of them, who posses the ranged attacks starts to attack rest of your "team". :P

Clerics make it so that fighters and other classes can keep attacking regularly, so they don't have to hit, potion, hit, potion. That's the point.
The only difference i see is that in your model it works for Clerics like they have static role that dont change much ...
While in Larian version they have choices, you can use your cleric as a healer, buffer and tank (if he wants to) ... but you also can use your potions from time to time and unless its cruicial your Cleric can do that one sweet thing that usualy players enjoys the most: Massacring hordes of enemies.

BG3. Fighter is up close and personal with high AC of 17 or 18. Gets hit. Second Wind. Attacks in return. Gets hit twice. Fighter needs some health. Potion and attacks. Fighter takes two more hits. Hmmm. HP is now roughly around 10. Superior Healing Potion and heals up to 20 HP and Attacks again. Gets hit 3 more times. Down to 5 HP. Superior Healing Potion back up to 15 and Attacks again. No cleric necessary. Just keep stocked on potions and Fighter wins without needing your healer.
Yup, he "can" thats the point.

Options ... so 1/4 of your party isnt necesarily reserved for dedicated healer ... yet he is usefull, since if that Fighter gets not "two hits" but "seven hits" potion is no longer enough.

So, is that somehow MORE fun?
Yes.
You want wait and heal > you can.
You want go and fight > you can.
You want support peoples effort > you can.
You want screw your party and go do something entirely different > you can.
That is charm of possibilibites.

There's no strategy or thinking involved. Wash, rinse and repeat. Just run up as a fighter or barbarian and bash the crap out of your opponents without fear of getting hurt because you can Bonus action a Potion every round if you need to.
Dont make me laugh.

(Oh, too late.)
Or you know what?
Please do ...
Tell me how "strategical" and "full of thinking" is your precious example ... where your Fighter or Barbarian runs up and bash the crap out of your oponents without fear of getting hurt ... because instead of lame, stupid, boring and nontactical possibility to sip single potion ... they have pro, brilliant, entertaining and totally tactical Cleric, that will heal them even better (bcs he have more spells, bcs some of those spells can on the contrary of the potion target them both, bcs those spells can heal them during the time between their turns when they are helpess)?

I litteraly beg you, elighten me ... what deep tactics are you talking about?
It's the Bonus Action Potions + Cure Wounds from clerics + Healing Word as well from clerics + allies being able to throw potions all in the same round.
Have you even tryed it in practice?
At least once?
Yes, your character becomed imortal for litteraly single round ... and you also just wasted 3 potions and 2 spellslots to ensure you dont change anything.
What is the point of that?
What would be the outcome of such behaviour?
After the round is finished ... your enemies end up just as healthy as they were previous round and gues what? They WILL attack you again.

Will you just spend yout turns healing each other eternaly until you run out of potions and inevidibly die?

Then you can save some time and reload it right now.

See thats the reason some of us concider this argument to be so false ...
Honestly:
- i would welcome if throwed potions healing would be split in half, since half of the healing liquid has ben spiled instead of digested ... but lets say nat 20 would avoid this, so there is some fun ...
- i would welcome if throwed potions would also give their target damage, bcs the vial dont dissapear, it still throwed projectile ... i would not even mind if there would me small (nat 1 for example) chance to cause 1 turn long bleeding effect, for the obvious reasons ...
- i would totally welcome if "missed" potion would be just wasted without ANY
healing effect ... leaving only small amount of damage ... so there is some risk involved
- and finaly i would totally welcome if our target would have to spend his reaction to catch the potion and drink it ... and if this would be allowed only after everything abowe would go well ...
But claiming that "throwing potions is incredibly OP and effective tactics that reduce meaning of any other healing class to zero"? Please ... even you cant believe that ... -_-
Don't suddenly give rogues another Bonus Action so they can Dash as an Action, Dash as a Bonus action and Dash a third time as another Bonus action - or allow them to Attack once with Sneak Attack as a primary attack, Attack again with the off hand as a Bonus Action and then attack a third time as a Bonus Action
Agreed >>
https://forums.larian.com/ubbthreads.php?ubb=showflat&Number=809477#Post809477