(Most recently laundering Russian oligarch money iirc)
Ordinary consumers don't give a damn about shady dealings of their banks, mostly because unlike phone numbers bank account numbers are not portable. Yes there exist regulations that banks have to assist with direct debit and automated order migration, but it's nevertheless a hassle to switch banks.
[1] https://www.t-online.de/finanzen/news/unternehmen-verbrauche...
This paragraph probably can be contested, if done in advance of signing the agreement, but if every other bank you approach have such a condition (to be fair, the only other bank I approached was SEB, also Scandinavian bank) spending time on arguing about trivialities while selling my soul to get an even worse rate did not seem like a worthwhile pursuit.
I don't think any banks here allow you just to have a mortgage agreement without an account at them- they deduct the monthly payment automatically. It might be possible with other types of loans, but I don't think it can be done with mortgages.
If you try to find a bank that isn't filled with criminal minds, you will never find one.
Now it can be claimed that cheap != low quality and there are certainly some exceptions out there, but generally you get what you par for.
The one time I had to do some non-standard stuff they were pretty slow and a little disorganised, but it still seemed better than the UK banks I've used previously.
The being said, living in Sweden before you get your digital ID set up and everything sorted out in all the right databases seems to be a massive pain. All my non-Swedish colleagues at work have bureaucratic horror stories of their first months in the country.
Even if you have cash, which most people don't, it's hard to spend. Grocery stores still take it so it would actually be useful in this situation, but other than grocery stores I struggle to think of any places in my city that accept cash. Maybe some bigger outlets do, not sure, but restaurants, cafes, takeaway places, small specialty stores and the like certainly do not take cash.
Denmark has taken measures to require most businesses to accept cash, but Sweden doesn't seem to have done that. I keep ~1000DKK at home for emergencies, but I haven't purchased anything with cash for... um... a long time. Perhaps once in the last year.