Some hosts offer a lot of bandwidth with their reseller packages compared to the shared packages so you have a better idea of what kinda bandwidth you are allowed to use Vs those 'unlimited' hosts. You have no idea where they will cut you off. That can be one reason. Another is when you open another site you just pop into your reseller account and make another account
No host should care if you are only running one site. Its your dime.
He was not asking for shared hosting providers. You did not even answer his question, Sandin0. You just posted a link to your hosting service....