Obviously you can do a SEPA transfer as well, but it's not instant and you have to type a long number and don't have a consistently good user experience. Bank apps lack good UX. Stuff like "send this friend 5 bucks again, this is his profile picture" and are a pain to log into.
I don't say I like paypal or banks, i actually dont like either. But paypal is just more convenient.
Scaling in 2D has 2 parameters, X and Y, in the example X was at 1 while Y was below 1. You are referring to a subset of scaling transformation where X = Y and the aspect ratio is kept.