djb

I too see the advantages and disadvantages of both traditional and electronics, the new stuff is pretty neat as Stuart points out, and for me its a pretty neat tool.
As for limitations of both, here's a recent example. Last week while camping for a week, we had our bikes along to do short rides. My wife and would ride into town to get groceries and a cafe visit. Some friends came up and we biked together as well. During a grocery trip where I had a good 25 lbs of stuff, my friend wanted to use his smartphone to try a diff routeback using a trail system that according to his phone was a few kms shorter. I said I'd be open to it as long as it wasnt too rough. We ended up on a farmers field path that was getting smaller and smaller and had to turn around, which while wasn't a big delay as we didn't have a tight schedule, no-one likes wasting time. Also, from the google map satellite shots, some roads that appeared to be paved were in fact dirt, again not a big deal but slower and I had to be more careful of larger.or sharp rocks.
End result it was more time to get back, prob 45 mins more.

A few.days later I went out for the afternoon on my own in a new direction, with a county map with me. I sort of just winged it and at some point the nice road I was on changed to dirt at an intersection-the paper map didn't show this either. Wasn't a.big problem, I took another road as I wanted to keep moving a bit faster and there were options.

So it seems to me that there's always going to be surprises, the important thing is to use judgment with the time you have and other factors. My afternoon of going off somewhere new was fun, I found a really nice spot right by the water for a snack and shade break and I got a nice 65km ride in.