It can do everything a normal keyboard can do but the best thing is that you don't have to be disabled to use it.

Ok, here's a little secret: late at night with the lights off I like to relax in bed with the MacBook Air on my chest till I drop off to sleep. I can't see they keyboard at that angle but I can still type with virtual keyboard. I might get somewhere between 15 and 30 minutes work done before consciousness fades and I shut the lid of the Air and shove it to one side. (I sit the Air on one of those "stable tables" with a couple of lugs to allow airflow under the device.)

[As an side: the Air with it's solid state drive has just got to be the best Mac I've ever owned - can't praise it enough. Solid construction, lightweight, super fast start up and thin as rake - a real take-anywhere laptop. End of plug for MacBook Air.]

Back to VK - the only other time I used virtual keyboard was in hospital where I was literally! on my back for three days. Never had a problem with it. Best $20 I ever spent.