I have the same concerns with N26 banking, which is also a application-based bank (there is a website, but you need the phone for the initial registration and for authentification on some operations). So far it works, although I have had to reinstall the Play store and the application several times after I had some troubles with either some updates or Google Services (but I think I noticed that the application does not rely on Google Services anymore - to be confirmed).

In any case, I have tested running the application in an Android virtual machine some years ago and it worked, so I'm considering that, if compatibility with Alien Dalvik is lost in the future, I can always get my money back and close my account using the VM or the Android smartphone of a friend. In the mean time, I do not pay anything for it anyway, and I think Revolut is free too.

At the moment, I'm glad I can use the N26 card, because I'm temporarily living abroad in a country using a specific currency, and I have not had to pay any extra cost in one year thanks to this bank, nor did I need to open a local bank account; I feel it's worth the risk of having to go through the trouble of a VM if compatibility is lost in the future.