I recently had a rather baffling experience trying to preemptively avoid this by downloading the stupid app right away, only to discover I needed the website version anyway.

I was attempting to add my Known Traveler Number to an already booked trip with Southwest Airlines, booked by someone else. I was able to link the trip to my account right away in the app, no issue. And I could see the KTN field for my ticket sitting there, empty, greyed-out, and not interactible. I opened up the moble version of their website, completely unsurprised to find it was identical to the app, except for the detail that the KTN field there was functional. Put in the information, changes reflected in the app instantly, and I was in the TAS-pre line that afternoon.

Why did the two versions obviously built from the same codebase have two different sets of capabilities? Why was the website the more capable of the two this time? I have no clue. All I know is I never want to be a developer at a corporation where I'd have to be responsible for this flavor of trash.