Not at all. You need it if you want the status bar on top. Mine stays on side and nobody cares about that.
BTW, I looked at many people observing their reactions. If they are going to make a call, almost nothing happens. The phone application works in portrait, Iphone owners looks disorientated for a second, everybody ends their task and return me the phone without further question. If it is for a quick bowsing session, the browser goes portrait and the only thing I am usually asked for is how to go back to the previous page (bottom right corner trick) or to type addresses (yes, I have to slide N900 open to show people the hwkbd). Usually iphone owners are the worst N900 users because after the first page, nothing works as they expect. Non iphone owner uses the phone with really low questions.
Contacts, Calendar, Multimedia, Photo, Calc and Angrybirds are other 'apps' I have on the screen. Many complaints against the calc, but all in all the people is able to use the 900 with really few questions.
Oh, and once an Iphone owner asked me the name of the browser app because mine was really better than the stock one... Ehi guy, this is NOT an Iphone, did you not notice it...?