There is no comparison between driving alone by map or a navigator - the latter is far better. If you are driving around an unfamiliar/distant urban area then you would have to have a very detailed map to be really useful in locating your destination - repeat that again and again and you have to buy yourself a small library of maps. Then step up to the situation where you fly into a foreign country, hire a car and set off. I have done this lots and lots of times, originally navigating by whatever map(s) I had, more recently by navigator. Not only is the navigator easier to carry but it beats navigating by maps hands down.
That said, I usually like to carry some map/maps that allow me to see long distance routes at a glance - possibly a carry-over by habit. You cannot switch off mentally and blindly follow the navigator's instructions, that has the potential of getting you into trouble.