Because it is convenient, but you are not forced to use Mobilt BankID because pretty much every service will still work with desktop bankid or the physical device (säkerhetsdosa) your bank gives you.
> However, BankID says they do not support /e/, and even if it works now, they say all risk is on me if does not work in the future. That is not a risk I want to take. I figure it's easier stay with what I know works than to backtrack in the future.
Yes, not officially supported, but if it's just Android it will most likely work just fine.
If you moved here from another country then I can certainly say you picked the wrong country, everything is digital, there is no "privacy", and as you said cash is disappearing rapidly.
Personally I quite like the bankid and swish system, it just makes my life so much easier.