It's not that he -wanted- to avatar Belcoot. It's that Belcoot is an avatar character traditionally associated to Gate. So, it's good form to actually ask if he minds you to avatar Bel. There's also the thing that it can be somewhat confusing to others due to association (someone else avataring Shady Thousand could be often confused with Elfboy, for instance, even though he's not avataring him right now).