He is not useless. SHINee wouldn’t be SHINee without him. It goes the same for the other 4 members. He’s improved a lot since SHINees debut (as have the others) and whoever thinks he doesn’t contribute ANYTHING to SHINee is obviously blind AND deaf.
Seriously, people need to start looking at Taemin and Minho’s personal growth since debut. They can actually hold a note now and they don’t sound tone deaf anymore. Then again, breaking out of puberty will do that, but regardless they have improved so much.