If you prefer to use it on your phones but have multiple passes, you can get them on the app on individual phones, but it's a bit of a PITA to set up. All of the passengers must have a RR account and the itinerary must be registered to that account. Here are the steps:
With each passenger, within 24 hours of boarding, you have to:
- Log in to their RR account
- Open the menu
- Tap "Look Up Reservations"
- Tap "View your upcoming trips"
- Tap "View Boarding Pass"
- (Optional) Add to Apple Wallet or whatever Android uses
I will caution you however, that there can be breakdown situations where mobile BPs won't work, and if that happens you'll have trouble getting your details straightened out. We happened to be flying the day that SWA had that server failure that resulted in very large numbers of flight cancellations; mobile BPs were not working that day, and those that planned to use them had to line up at the gate to get paper BPs printed; it was a zoo scene. Also, if your flight is delayed, make darn sure that you don't run your battery down before boarding, or you could find yourself in an awkward position.
I also prefer paper because I don't like having to juggle my phone along with bags when dealing with TSA and boarding the plane, because I have an unfortunate habit of misplacing my phone. (It's no biggie if you lose a paper BP; you just print a new one. Losing your phone is something else entirely.) I just prefer to have my phone turned off and put away in my bag at those times.