They are European, certainly the Euros could come up with some regulation to force banks etc to support a Euro phone. I’d actually welcome this as more competition is better and we can’t seem to kill the duopoly here in the US.

They will be able to do banking at least once the legislators tear down the walled gardens in a sensible way. Are the security benefits from the Appstore/Playstore real or security theatre?

I'm pretty sure that, if there are security benefits, they have been artificially tied to the use of the company's distribution method, that coincidentally really needs to be sending usage statistics, monitoring, etc. Surely there exist no conflicts of interest to be found.

Looks like the Swedish bankid at the very least actually does work on sailfish[1]!

Not sure about equivalent apps for other regions, but I don't see why they shouldn't work.

[1] https://forum.sailfishos.org/t/swedish-bank-id-swish/11781/3

If you don't expect Google Pay / Apple Pay to work? Yes. There's a thread on the SFOS forums dedicated to this [1].

[1] https://forum.sailfishos.org/t/banking-apps-on-sailfish-os/1...

I just switched to a Fairphone 5 with e/OS, which is a de-googled Android (it uses microG), and am pleasantly surprised how well everything works. My banking apps work, contacts and calendar lived on nextcloud already, the learning apps I use work. The two things I have to get used to is not having google maps, but the map app on there has also worked fine for me so far. And casting to a Chromecast doesn't really work for me, but I can live without that.

Afaik there is an android compatibility layer but I don't know if it allows banking apps to works

The vast majority of people on this site can afford a couple hundred dollars for a basic Android phone that's used only for tasks like that, and as a bonus it's safer than having banking apps on your main phone. Anyone who isn't willing to spend a couple hundred bucks on the freedom to run whatever software they want on their phone probably doesn't consider software freedom a priority anyway.

You are allowed to have more than one cell phone.

If you use it without compatibility layer it's probably on the same level as a kaios phone. There is a lot of slop on the sailfish store.