Many places, now do not readily accept cash, many say their preferred option is to pay by card, because of the security implications of handling cash, someone has too physically take the cash to the bank, deposit it, often it's a two-man procedure, taking staff away from their duties, and of course the banks charge for the time it takes to count, then credit the money,
I agree with those reasons but if I wish to pay with cash but have any reason to doubt its convenience for the retailer I usually say eg ‘do you prefer cash or card’ and my experience of the reply is usually ‘either is fine’.
Just my experience of course.
Why might you doubt the convenience of a payment method for a retailer, and why should that matter to you as a consumer?
If a business accepts cash at all, then they should accept it from everyone in all circumstances (unless informed in advance, e.g. a sign at the entrance saying that cash is only accepted at certain times of day).
I will use the payment method that I find most preferable. For me, 99% of the time that will be card, but when I want to use cash and the shop accepts it, they should not try to guilt me into paying by card just because I can pay by card.
Signs saying "card preferred", or less often, "cash preferred" really annoy me and will prompt me to use the method that is not preferred (unless I already planned differently before seeing the sign). Whereas if I'm aware a shop is card-only or cash-only before I enter, that doesn't bother me at all.