I do use both cash and cards, but I like cash better, it's smarter to use. Cash is accepted everywhere while cards may or may not be accepted, there may be a charge or minimum purchase (because the vendor gets charged), or the system might not be working today.
Cash always works, cash can be stolen or copied, but it can't be hacked, while cards/e-accounts/crypto currencies can be copied, stolen, and also hacked, and far more easily.
I can't imagine cash ever completely going away, but most people in society are dumb so who knows.