Yeah, seriously. When I am walking around and I need to do something quick on the screen, I very much prefer to have one hand free just in case. That's the reason I chose a E71 over an iPhone (and why I didn't end buying a N97): because I can use it decently with one hand, and very speedy with two hands. The situation is different when I am sitting in my house, then I could spring out the keyboard.

Another reason: around here in the third world (a market Nokia likes) there are plenty of people waiting to snatch your phone and run away. Common targets are people that have their two hands busy. And I feel my phone safer when I grab it fully with my hand (I have big hands, though). When I carry something with two hands, it is very easy to grab the phone by the middle and snatch it away.

And finally, and tbh, I find the N97 keyboard....not so good compared to the E71's.