I think his time is better spent in other ways. I don't remember being able to easily use a keyboard listed as a prerequisite for being president. That's what secretaries are for....and in McC’s place, Cindy has been doing it for him. He dictates, she punches.
Yes. Of course. It wouldn't surprise me if many CEOs of large corporations don’r use a computer. They could think they had more important things to do, and let others do that for them.
If the rebuttal works, fine. But I think it would be wise to check with McCain to see if that rebuttal is the one he wants others to use.