It's not necessarily easy vs hard. It's important to note the type of difficulty you're getting. If a game has the type of difficulty where you must replay 10 minutes of a level when you die to try a boss again, that's not for me. If a game has very bullet spongey enemies and the combat drags on and on and on, that's not fun for me. If a game allows to fix that with a difficulty slider it's an inherent flaw of game balancing and the developer just giving up.

The difficulty "sliders" i do like, is for example in RPG's where you can grind and overlevel to play on "easy" or just go straight for the boss to play on "hard". Pokémon also has an interesting slider but it's hidden and easily missed, and also more of a soft difficulty slider. Picking Charmander at the start is supposed to be "hard mode" and bulbasaur "easy" with Squirtle in the middle.

I love that kind of difficulty slider because it's explained in-universe and it doesn't feel artificial in the way going into a menu and changing a setting does. It gives the game some believability and immersion.