To me, playing AD&D isn't about getting there quickly. In old school fantasy Paper and Pencil, resting is just as much about managing player resources which is necessary for game balance, as it is a narration tool. It serves verisimilitude by reminding players that their characters are people, not comic heroes and that one false step can ruin their camping holiday. New players often still have to learn the scope of the world they're playing in, especially when coming from modern settings to a fantasy map, like Forgotten Realms. It's a bit like sending them to scout camp. We're used to having information instantly available and having almost any place in the world in reach of maybe three days travelling in leisure clothes. Then, most players, including myself, tend to idealise and overestimate their characters. This tends to lead to player expectations that their characters can work a 24h-shift without exhaustion or mental issues, walk 40 miles in worn-out boots, just skip-a-dee-doo-daa over broad streams and mountain ranges and then arrive just in time to humiliate the villains in combat. That would have reduced the Lord of the Rings to a YouTube Short.

But if you happen to end up in my campaign world, you lose the first of your fresh character's precious few hit points to sores from bad footwear while checking out town libraries for the mysterious monster that attacked your village. Then you find out that you'll have to travel to the big city to talk to a sage which is over a week of travelling due to resting and difficult terrain, even though the city is just next to the town on the large map. No, you won't make it there tonight! With a dangerous stretch of forest in the way and assuming a classical medieval Europe-flavoured map, before you reach an area where anything with significant hit points wants to bite you, your enemies would be humidity, hypothermia, bringing or finding clean water, injuries from falling in difficult terrain and crossing rivers without drowning, losing equipment or getting sick in soaked clothes. Lack of sleep can kill under these conditions. Only when players have tasted that mud and learned not to overpace, to conserve arrows, make plans what to pack for a journey, as well as keeping vermin out of their campsites, their throats wet and their feet dry, they're ready for the next chapter.

But even when you've become Lord Badgerbane of Examplewood and returned from your first successful adventures with solid footwear and spells that keep your tents clean and safe, you still have to consider exhaustion. With wizards, it's clear that they have to memorise spells. But that doesn't mean a fighter won't run out of power. Muscles burn calories, micro traumas accumulate, lack of sleep wears down your reaction, focus and eventually determination and mental health. Yet, while you're cuddling up in your bedroll hoping your body will stop hurting, the undead you failed to destroy and only made angry are catching up and may reach you before your group reaches the temple where they have the thing that gets rid of angry undead. I mean, who would cast Sleep on a skeleton? Undead or other supernatural creatures not having to sleep only really comes to play when considering that it not only gives them a tactical but also a strategic advantage over yapping mortal meat sacks. Resting also automatically arranges for camp and tavern encounters and lots of other fun, at least if you're the DM. As a player, you want to avoid having to rest, of course.

After completing these low- to mid-level stages, my current group hit their Spinal Tap-stage. It was no longer "get away from my gate, scruffy!" after emerging from Examplewood, looking like a shrub and smelling like fish, skunk and bear. It was "Welcome to our humble town, Saer!" because they'd teleported in clean clothes. They'd finally beaten the system and got their Rings of Sustenance, Potions of Vitality, Girdles of Giant Strength, and suddenly all kinds of absurd things started happening just because they could, and because they'd become the rock stars of their world. The contrast to what they had learned before really came to play here. And, not resting became yet another source for DM atrocities because the potions were becoming a habit, but couldn't defeat all side-effects of not sleeping. Once off their juice, characters found they'd slept four days and developed all kinds of insanities while on it.

Of course, it depends on your style of play. If you're playing the same characters in the same world for a quarter of a century, keeping these things in mind avoids lame reboots or retcons. If you only have an evening for a story from start to finish or generally start at the dungeon entrance and just want an evening of fun chopping up monsters with your friends, then resting shouldn't come into conflict with having fun.