I've read "flexibility" here compared to a computer RPG, not a people RPG.

I think that’s not much different. Players don’t want to hear the local shopkeeper’s thoughts and feelings imo. It’d be tedious. They canonically don’t have any useful information for you. It would just mean that they take a long time to talk to and worst case require you to respond with a level of sequitur and politeness.

I could see it for waifus I guess.

I’m prepared to be wrong on this.

As a human DM, your shopkeepers 'canonically' don't know anything because you would have to devote brainpower to animating them with lives and relationships and things. You're thinking... 'Oh no, they're asking him about his family, and if I give him a brother, I have to give him a job and if I'm not careful, I might say something like "he says his brother has a job in the city watch", and someone will write that down, and then later they'll decide they need to bribe a watchman and they'll want to find the brother and... damnit, the shopkeeper will just say "I'm sorry, I'm too busy to chat"'.

Whereas a GPT LLM DM has no such issues! It has no forward plan for 'canonically' how this story is meant to go! For all it knows when you start talking to the shopkeeper, asking him about his brother might open the key to discovering a ring of bribery and corruption in the city watch, which leads you to the trail of a Big Bad....

The only thing, canonically, the LLM DM is trying to do, is make the story keep feeling like a D&D story. So the things you ask about are going to be the things that matter to the story.

And that might turn out to lead to more interesting stories for players than playing 'guess what the DM was thinking' games...

We were talking about computer rpgs there. It’s different, because computer rpgs need more structure to fit in the game mechanics.

I also just disagree. Open ended stories are not good for D&D. Especially in a group. An LLM, including this one it seems, can have a structure it wants to follow.

Players should not be trying to guess what the DM was thinking. It should be placed in front of them quickly.

Downtime in the city is just bad

Stupid roleplaying game players, wanting to role-play.....

You get that there are different things different groups get out of a D&D campaign right? It has a number of systems - combat, magic, role-play, world building, character development, and, yes shopping... many games don't use all of them, and how they balance time among them is going to vary according to taste. Right now, someone seeking a GPT4 DM is not looking for a beautifully crafted narrative arc and a satisfyingly escalating series of intricately balanced encounters; they are looking for a DM who will take player ideas and run with them in a way that a human DM would not tolerate.

That means they're foregoing the guidance of a competent DM who knows how to craft a narrative, and taking some of that responsibility on themselves.

And if they're having fun doing it, then isn't that okay? Even if they end up playing a game that isn't like one you would run, or want to participate in?

Matter of taste; many people prefer roll-with-the-punches GMs to “tall walls” (or in the more common negative description, railroad tracks) GMs.