I guess what I'm saying is twofold:
-- a computer is no substitute for alternate methods of real-world discovery, but it can become so preferred as a tool that it's easy to discard the others entirely (which is a costly mistake in the long run),
and perhaps more importantly,
-- we as parents may have trouble placing controls on usage because our kids have the skills to do things to work around them, but not the maturity to know why they shouldn't.
I really, really agree with this. And since I have a daughter who is obsessed with being older and being treated as an adult, your second point is particularly relevant.