N26 requires Google spyware, Revolut too, and I think Wise too. Some banks will further cancel joint / shared bank accounts when one partner moves to another country (even temporarily). And some banks are mobile only, meaning that while they may work for some time without US tech, they may suddenly change their mind, not tell you, and you'll find yourself locked out of your bank account or their payment methods.

And whether things are illegal or not doesn't matter too much unless you have money and resources to fight it. As an example, I had a lawyer friend who suddenly got a bill to pay for the previous tenant who hadn't paid the internet bills for months. Of course it was unjust, but the telecom company still put a lean on his account. Despite being a lawyer, it took said friend about a year to fight it (and win). But remember, this was a lawyer. I would have to hire a lawyer, take the thing to court, and hope everything is compensated.

If this were a reality where I could put my life on hold to fight stuff like this with state aid, there's no doubt I'd do it, but in this reality? You've gotta pick your battles.