You are right on that Frank.. They tightly control all aspects which means they don't have any conflicts with too many plugins or errant code. They only allow things so there is no conflicts in code. This means you don't have anyone call to customer support in a panic because a bad plugin took your site down which they don't want to have to fix... My wife has one of these and it works great for her..
Me? I want the control.. :-) If I break it, I beat my head against the monitor until me or the computer is bloodied and one is declared the winner! (Usually its the computer but I sometimes have my day also!)