Actually, their advantage is being instantly reconfigurable via software, while their disadvantage, as I've mentioned twice already, is that there's no meaningful tactile feedback for differentiating one key from another or differentiating input areas from non-input areas without taking the user's visual focus away from information displays. You don't have to look at a conventional keyboard to orient your fingers on it or look at a physical switch, toggle or dial to know what position it's in. You do have to do that with virtualized control surfaces. I asked this already but I didn't see an answer from you:
Have you ever used a touch (or multitouch) interface you didn't have to look at?
The only reason for touch keyboards is that they look prettier. They're not only not more user-friendly, they're less user friendly.
Now as for touch or multi-touch displays, who says the ones on the classic TOS Enterprise can't have been that?
"Now I did a job -- and got nothin' but trouble since I did it, not to mention more than a few unkind words as regard to my character, so let me make this abundantly clear: I do the job... and then I get paid. Go run your little world."