I for one say yes. Wild difficulty spikes hve been one of the banes of my 30 years of gaming. Nothing better than being able to solve that with a trip to the menu. It might be cheap or cheating, but its added many hours to my gaming so I guess it's worth it.
I don't see why not. It does work both ways. If a game is getting too infuriating then it's like would you rather redo the last 6 hours or change the difficulty right away. Also for people who find the current setting not challenging then they could dial it up to a harder setting.
If a game is not gonna have the option, it needs to offer some form of grinding to make the character more powerful. Even action games need this. Like Bayonetta- going to previous levels to grind gold. Whereas, for example, its hard to grind in a god of war game because there's only so many orbs to be found and you can hardly go back to previous levels. So if you truly can't beat a boss, you're in forna rude awakening. And changing it too easy is for keeps. Just let me do more grinding.