If you're in a "tourist destination" area, then no worries, I'm sure they will offer credit card as a payment option to keep you in business, but it's likely to be more expensive than paying using PIX.
When I was in the south of Brazil I used the "iFood" app (biggest food delivery app in Brazil) and I could only pay using PIX. In other regions, other options were available such as credit card.
Even if you need to do a PIX as a traveller, you can simply pay in cash to some person (hotel recepcionist I guess) so they can use their account to pay the PIX for you. Technically this person will scan a QR code and pay using their bank account.
If you want to have a PIX account yourself, at the moment you need to have a bank account in brazil afaik. After having your account, you have to register it using specific types of identifier, for example your mobile phone. Non-brazilian numbers are accepted in the standard, but not all banks accept them for now. It certainly will go over changes. It's a relatively new technology.