I'd think it has to do with the after care of it. Use it and now you have to be the one to clean it, worse yet if it accumulates dirt in the whole oven casing, gonna have to be you or become the office asshole. So just use the dinky toaster and have nice toasted bread with a thing people are more accepting to be a little messy/ permissibly dirtier cause of how much harder it woulb be to clean.