I have. It usually works fairly well. Some service providers do use the service, but in my experience, most do not. I wish that most did though- it is very discreet.

I have used it for deposits required by certain providers.  It works very well and is very discreet.  I too wish more providers used this service.

I abhor the thought of prepay and I'm highly unlikely to see a provider who insists on a PayPal deposit. I tried once with a porn star but PayPal dropped the ball and I used my credit card.

Use of PayPal upon arrival is subject to all sorts of computer-age vagaries too numerous to recount.