I've used mobile BP's once or twice. I always check in remotely, get the mobile BP on my phone, but then when I get to the airport in time I still print at a kiosk.

Paper is still faster at the TSA checkpoint. And I'm don't trust my phone 100% to not rotate the image, go to sleep at the inopportune moment, etc. But in a pinch (e.g., if I was running really late), I certainly *could* do the whole process with a mobile BP. It's nice that the option exists.

The one flight where I saw a LOT of pax using mobile BP's was a FRA-MUC LH flight. Makes me wonder if they've advertised the feature prominently within Germany or their domestic security process more quickly handles the mobile BP's.

In that U.S., it hasn't been advertised much at all - just an email or two and then it's an option for someone who is paying close attention during check-in.