Is that legal now? (I am making reference to GA generally, not this particular flight). In the past, the FAA would not have permitted a pilot to make navigational decisions based on a consumer device like that, although he could have carried one for confirmation. (a lot could have changed in the 15 years I have been away).
Well, VFR pilots are supposed to use sectional charts for pilotage, but GPS makes it so damned simple. Not illegal for VFR flight, but a cautious pilot would use both. Cutting corners is something we all do every day, rarely does it bite you in the arse.