A friend of mine travels a lot and if she's traveling at night, she'll sometimes send me a WAZE alert when she is on the road and I'm able to follow her home on my mobile device to make sure she gets home safely. Just a little blue dot moving through a map. I think that's pretty cool.
It's not that I stare at the screen the whole time but every few minutes I'll take a glance just to make sure the dot is still moving.
I see nothing wrong with this.
I think of it a little like using flight following when you are flying cross country VFR. It does not make your flight any safer but someone will know where to look for you if you have difficulty.
On the other hand I think that people tend to lose situational awareness while they are playing with their phones. This is especially true when people are driving. I wonder how many people have caused or got in accidents while playing with Google Maps?