Just for discussion purpose, as guess street directory is going to be a thing in the past sooner or later.
If gps failed, or rather many are using hp's gps/aps to find their way around town nowadays.
Handphone can fail also. Nothing beats a manual backup. Just in case.
But one advantage if you call it that. With street directory you need to park the car then look for directions instead of using handphone or GPS and looking at it and then not focusing on the road. I try my very best not to use GPS unless someone is next to me in the car. Very distracting.