It runs sailfish OS on the Jolla hardware. It can be compatible with android for apps (such as the google play store) but can also be independent with app stores like fdroid. It is unlikely you’ll have any issues with banking apps.

I can’t speak personally to the camera. Typically android and iOS do a better job with perfecting the camera app over open source apps. However, sailfish did release a camera app for Jolla back in October. My guess is it won’t be as good as iOS or android; not due the hardware, but rather the app that processes the pictures/videos.

Here are some alternative camera apps to check out and see what you think.

https://alternativeto.net/software/open-camera/?platform=f-droid

Also, here is sailfishOS’s main page so you can check out more about the OS: https://sailfishos.org/