Do you need a keyboard?

I haven't ordered the Surface yet because I don't have the extra cash available, but when I do get one I'm pretty sure I'm going to skip the keyboard cover. When I imagine my use cases for a tablet, it seems like the cover is going to be in the way a lot more often than it's going to be helpful. I know you can flip it around backwards, but if that's how I'll be holding it most of the time then why should I pay extra for it at all?I'm typing this post using the on-screen Windows 8 keyboard on a Samsung Build tablet and it's pretty fantastic. I might be able to type slightly faster on a touch cover and reclaim some screen space, but then I'd have to find a desk instead of holding it in my lap. With an on-screen keyboard that's this nice to type on, why are Microsoft and OEMs putting so much emphasis on attachable or dockable keyboards?What do you guys think? Is a keyboard really a necessary part of the tablet experience or is it just a novelty to get people to pay more for their gadgets?