I do have a £5 or 20 note as an emergency money in my bag and £20-40 in some drawers at home. E.g. to buy lunch if I come across a food stall that doesn't accept card payments. Rarer and rarer is it needed in the UK, and when I lived in Norway it was months between each time I needed cash.
I do however have spare debit/credit cards at home and my bag as well in case I lose my wallet. (I have never actually lost a wallet, but have left it in my coat/trousers at home etc)
With more and more stores (especially in Scandinavia as the OP details) no longer accept cash, and have not accepted cheques for decades, I am not sure your solution is a long-term solution.
[1] https://www.bostonglobe.com/business/2016/08/03/paying-cash-...
[2] https://business.financialpost.com/news/economy/no-cash-sign...
I have $2 000 cash at home.
Once I’m home I can write myself a cheque, and with my passport, easily withdrawal more money at any bank (or grocery store).
Also, if a natural disaster happens (earthquake, fire, flood, hurricane, Norsemen with iPhones disembark on our shores) I don’t have to rely on any network to buy something. I just pay cash, or write a cheque.
Cash is very robust. (Booze, cigarettes and gold more so, but that’s another story)