Ryanair basically invented most of the dark patterns that are now prevalent in all travel websites. Back then, the experience was so awful that it was comical (and even inspired a song[0]). Therefore I'm not surprised that they are the first to mandate you install their app on your phone. All other companies that have dreamed of this will be quick to follow suit.

Notice the euphemism of calling this "going digital". Everybody is already digital, using a pdf reader on their phone at the terminal, despite some companies discouraging this practice. That's not digital enough, is it?

[0]: https://youtu.be/Id-zzOGnN6A?t=102