i thought its common to have iPads on stage for sessionists?
definitely common in church settings too for songsheets, easy to just click and share with all on the spot if there are any changes live. Also some use it to control monitor mixes. Sounds fancy but its actually relatively simple.
For songsheets usually pdf, just swipe left/right as if to turn the pages. It's more of a backup plan as I think most musicians do memorise the parts.

I do have my iPad with me... not really for the purpose of using it live but long boring soundchecks i'd be reading my magazines / fb etc. Haha