I go to Canada multiple times a year, and usually 1 true international trip. Sometimes I just check in at airport (with the family, usually have bags anyway), but often I use the app, and I can’t remember having an issue in the last several years. The biggest thing for me is when traveling with a lap infant, as has often been the case, it won’t give me mobile BPs, but interestingly enough, I’ll always get printable BPs. Those emails always say on the top that the following passenger BPs aren’t included, and lists the lap infant and the adult they’re connected to, but without fail, the BPs for all will always be there. Better than DL, which won’t let you check in with a lap infant using their app or kiosk at the airport, you always have to use an agent.