It does depend on the business. As a jobbing musician, I spent most of my working life playing either solo or in several pickup bands, as well as running my own. Virtually every gig was paid in cash, with the occasional agency work paying by cheque.
Admittedly a bit of a minority niche, and I would assume if you ever got famous you'd ditch the cash, but for hundreds of musicians bumping along, just about making a living, cash is indeed still king. And, of course, for the black economy, which is all that keeps many cities and people afloat, it's essential.