you can play osu! offline by logging out, (clicking your pannel on the main screen and clicking log out) but you're right. there is no way to play online and compete in rankings and leaderboards, as well as play in multiplayer.
I do get bad accuracy but not why I wanna delete. I make real world mistake and I lie to people that I care to I was fake person but I want to be real now so I make new accounts so I can be myself and if keep playing on this account they will know who I am and everyone will leave me. Very much my fault, I'm sorry to all..