First and foremost, it saves me time and mental energy by allowing me to leave the house without worrying about making sure I have all of the information I need. I often get in the car with just an idea of where I am going, and then find the address while driving and use the phone as a nav system. I use voice recognition so it generally only takes a few seconds and minimal distraction. Along the same lines, if I am out driving and I suddenly think of something I need to do, I can find the place I’m trying to go without having to return home. Finally, if I’m idle at any time I can use the phone to write and send e-mails (or other basic tasks) that I would have otherwise had to do at another time.
This is just one subset of time-savers, but I would say that it saves me about 15 minutes of time a day by itself.
Doesn’t it tempt you to waste more time than it saves? E.g., websurfing and gameplaying?
A lot of the time you waste doing those things was already wasted. For instance I am posting this while waiting in a drive through for breakfast, but this is exactly when I would be playing random game if I was not posting here.
Edit: And well designed smartphone games (which is not all of them) load shockingly fast. I have actually played smartphone games while waiting for other slower games to load on my computer.
Also, since smartphone internet browsing is a bit uncomfortable, it might prevent you from booting up your computer as often and ending up spending an hour.