I'm guessing the ANO rule that requires a current chart to be carried, was originally drafted a looooong time before the current generation of sophisticated, hand-held GPS devices were even conceived. Like many rules, it simply hasn't kept up with the ever accelerating world of technology. No doubt there will be an amendment in the future, which will be obsolete before it hits the [metaphoric] press...
In the meantime, i don't see how, say, an iPad with SkyDemon could be more distracting than a 1/4 mill map supporting a cross country track crawl? The great thing about modern GPS is that a quick glance is all that is needed to confirm you're still on course
