Seeing as my iphone regularly goes five or six days between charges, I am not the target market for this thing.
I stuck with my dumbphone for a very long time, but finally the need to have something that took decent pictures caused me to get a cheap used iphone. Now I use it whenever I am away from home, as a camera, note taker, memory aid, and texting device. I use it as a telephone less than once a week. It has been immensely beneficial to me, and there is no way in hell I will ever go back to a dumbphone.
My secret to not letting the phone take over my life is simple: no social apps whatsoever, no games, and without exception, no apps other than Imessage are permitted to send notifications. It pings me when I get a text from someone in my address book, and it rings when someone tries to call me, and that is all.