I started a new Minecraft world after a long time, the last time being shortly after the update that added the new cave biomes and changed world generation and I'm instantly reminded of how useless copper is. Can't make tools with it, can't light torches with it, can't use it as fuel, and it's all over the depths you'd typically find iron and coal, the two early ores that actually do those things
Smelting it gives a nominal bit of XP. If you have an auto-smelter setup with a switched output hopper so that you can collect banked XP, it can save your ass when trying to enchant or repair gear in early game, especially if you're smelting with lava buckets (since they're renewable anyway). Once you throw Fortune III into the mix, copper is absurd for this.
Motherfucking lightning rods. Do NOT underestimate them. Building a villager trading hall? Make goddamned sure it has lightning rods. Villager breeder? Lightning rods. Only you can prevent villagers getting turned into Margaret Thatcher.
Copper blocks (and slabs) make a nice alternative to stone for things where you just want to use a lot of throwaway blocks, e.g., for spawning pads in mob farms. Endermen can't pick them up, they're opaque, and you have access to plenty of them. They also have a nice grid texture to them (similar to iron, smooth stone, or polished diorite/andesite), so that can be helpful on complex builds where you want to be able to eyeball the dimensions.
Other than that, though, yeah. Pretty damned useless, and only exists as a gateway to inventory management hell, not unlike the overworld stone variants.
haven't played MC in ages but that seems like exactly the kind of thing where I'd hoard it for weeks, and then eventually snap and build an entire tower out of copper blocks
back when I did play I also tended towards mods like thaumcraft, and they always have some kind of "garbage disposal" mechanism that extracts value out of literally anything. rendering down boatloads of useless ores into "metal essence" or whatever to fuel the enchanting machine.
Those annoy me less since I'm not compelled to mine them unlike copper and the new rock variants just register as background to me. With ores I feel like harvesting all of them from my mineshafts for completeness' sake, especially since the shader I'm using adds a slight glow to most of them so they stick out. I already have chests full of unsmelted copper
What about how normal digging used to result in some stone, dirt maybe, gravel maybe, and now just going to mine fills your inventory up with seven different variants of rock ? I was already sick of having andesite and diorite and now there's like a different block for every existing block but it's deepstone or whatever. I hate how cluttered inventory gets three minutes into mining.