Sorry but that's a bit too paranoid for me. As you said currently businesses have to accept cash so why do you need a law that says they have to accept cash? It's already the law. If you ask me this is a dumb requirement. Why should businesses have to accept cash? They aren't forced to accept credit cards of EFTPOS. They should be able to choose any kind of payment they want. If you don't like it go to the next business.
If you make society cashless, if you give businsses the right to be card only, to not handle cash; then most of them wont. You make cash almost useless.
How do you know most of them won't? There are cashless societies out there and most businesses still take cash.
Nobody is trying to make cash illegal.
Finally I am not buying your story about how your friends don't want you pay them in cash. You shouldn't have added that to your list of woes.
How do you know?