Minecraft has so many useless features that nobody uses, and if they were removed, nobody would care. Here are some of those;
Beetroots - why grow a crop that gives you one single food item that restores a petty half a hunger when you can grow carrots or potatoes, both of which drop multiple food items that restore several hunger bars?
Furnace minecart - powered rails exist, rendering these completely useless. Even if you don't have powered rails yet, furnace minecarts are just too hard to use. They can only hold one coal at a time and choosing which direction it goes is annoying too. I don't see why they haven't buffed these yet.
Llamas - I could not figure out what the point of these were. You can ride them but you can't even control them. Someone told me their purpose was to carry more items, like have a chest on them and store items in them while pulling them on a lead, but.... why do this when you can just use a donkey/mule? Or a shulker box once you're late game????
Wandering trader - all of their trades are completely garbage. Except maybe the gunpowder trade, but he doesn't sell this consistently enough for it to be practical.
Bottle o' enchanting - such a tiny amount of XP that simply isn't worth it. Sure, it's fine when you find them in chests, but they are entirely NOT worth purchasing from clerics.
Conduit - so why use this to breathe underwater when you can just remove the water entirely, make air pockets, or place down doors? I used this solely for the "How Did We Get Here?" advancement and that's it.
Riding pigs - why ride a pig when you can ride.... a horse? It's faster, doesn't require a carrot on a stick, can jump higher, is tougher, and can wear armor. And donkeys and mules can carry things for you.
Wolf and fox - overrated if you ask me. They don't help that much at all with fighting mobs and usually just get themselves killed
And finally, here are some more pointless mobs, but I'm putting them all in the same section due to not having much to say about them aside from just that they're pointless - panda, parrot, bat, ocelot, endermite, glow squid.
Do you disagree with any of these? And if so, why? And do you have any to add to this list? If you do, I will add them to the post and credit you.