I was one of the later people I know to get a smart phone (I saw no point in it) but since I was working in that industry I eventually got a smart phone and now I can't see ever turning back.
Smart phones are pretty much as useful as you make them really... If you take two phones that belong to two different people with different interests (who know something about how to use the phones!) they won't look a thing alike... speaking of androids anyway. Boyfriend and I both have androids and he primarily uses his for quick calculations and playing games and therefore the whole setup involves an entire calculator screen and several screens completely devoted to gaming and chatting. My phone is my thought collector and rememberer, so I have my scheduling app integrated in to the point where my phone reminds me several ways when I have something coming up... I also have chrome to phone (yay for sending web pages back and forth between my phone and my computer!) and google drive, which allows me to work on a document simultaneously between my phone and my computer, depending upon which is available. Quite useful with working on writing things. The ability to instantly look anything up tends to settle arguments before they begin as well! I also use it to listen to nerdy podcasts, like Stuff You Should Know on my way to work so that I can gain even MORE useful knowledge to inflict upon others And I love the kindle app
In other words, it's what you make of it