Pretty much every PbtA game I’ve seen (maybe with the exception of Murderous Ghosts) does all three in different proportions, and it’s different for each move.

For example, spending hold from a move is explicitly “when you want to, just do it”. “When you offer Mercer a gift,” is almost 100% triggered by the fiction. “Acting under fire”, though, is a tool for the MC to disclaim responsibility sometimes, and it’s almost always a judgement call in the moment – you bring it in when you think bringing it in will be fun.

I don’t think there’s a “right answer” here. It’s all these things.