Earlier quoted context omitted.
To be fair the only place where I saw taxis accepting cards as a rule was NYC Practical, still a bit weary though especially without EMV readers
Go to any place in northern Europe and it's basically only card.
I normally have a few may 100 to 200DKK in my vallet, because the credit/debit card system do still fail. I haven't run into anything in the last few years where I could pay with card or mobile payment.