I have an iPad Air that has gone through several different "careers" over it's life. It started out a as work note taking tool for handwritten notes and PDF editing but eventually started doing less of that.
Then it became the toddlers and kids' play thing with lots of children's apps that they enjoyed using but as time went on they transitioned to just using the same apps on my wife's and my phones.
It's current life is as a substitute for on stage notes. When speaking I hate shuffling through papers and not being able to edit them on the fly if an idea pops into my head right before I go on stage. It's really convenient and fluid to use and though I get a lot of concerned statements about the fact that technology can fail on you at any moment I really have zero hesitation about relying on it even without a backup.