When you are playing in a survival world (singeplayer) diamonds shouldn't be a big problem. You might not have them immediately, but once you have a few your as good as set. You got yourself a fortune pick, mending armor and mending tools. After that you don't really need diamonds anymore. You can set up a few beacons.

While in multiplayer diamonds are mostly used as payment (vanilla servers). Which is nice, because they have a use and there is still a need to get diamonds whether it's through mining or selling.

That feeling is missing on a singleplayer world. My gold and iron are still being used for villager trading, but my diamonds are just laying there and I haven't been mining them for ages.

Isn't there any way diamonds could be a little bit more useful in the endgame?