Build Battle used to be one of the gamemodes on Cubecraft. While I didn't join the server when this was still a thing, I do know that it wasn't a big success. Build Battle was removed due to its unpopularity. Don't quote me on this, but I don't think Cubecraft will ever re-add this game, as it would be a huge risk, but also because most of the other "big" servers have this as well. Since other servers have it, they might say Cubecraft copied the gamemode, which is against Cubecraft's principles. :)