It’s legal tender for debts. Not payments.

Depends on the jurisdiction I guess ? I just checked, and around here cash is the only type of payment that cannot be refused, and if they get caught trying they would be fined 150€.

A debt must be incurred for them to refuse it. If one walks up to a counter to pay for something, there is no debt and a business can refuse to take the cash.

Lots of businesses in my city refuse cash transactions. There's minor controversy about how it tends to shut out marginalized people, but AFAIK it has survived legal challenges.

It doesn't matter that cash is "legal tender" if the business can just refuse to enter into the transaction in the first place.

I guess it's going to depend a lot on whether you can just plop down the money (and change) on the counter, and leave after the service has been done / with what you bought... or not (because you have to pay upfront for instance).