Weird, I've flew out of SFO two weeks ago on United, and their online check-in never works for me so I just do it at the airport and get a paper boarding pass. I didn't run into any issues. Line was short (mid morning on a Thursday). They have a bunch of self-service kiosks to check-in and print passes.
It's never crossed my mind that an airline app exists and I would never consider installing one. If they don't want to provide self-service kiosks or a working website, I guess they'll have to have more demand for agents. Same with banks: there's no check deposits through their website, so I go in person when I need to do that. Installing an app is just not even on my radar to consider.
I'd also never rely on a gate number from my phone anyway knowing that it could be out of date. I'd have to verify with a departure board or sign at the gate anyway, so I'm just going to start there.
It's never crossed my mind that an airline app exists and I would never consider installing one. If they don't want to provide self-service kiosks or a working website, I guess they'll have to have more demand for agents. Same with banks: there's no check deposits through their website, so I go in person when I need to do that. Installing an app is just not even on my radar to consider.
I'd also never rely on a gate number from my phone anyway knowing that it could be out of date. I'd have to verify with a departure board or sign at the gate anyway, so I'm just going to start there.