There are webcam studios in Colombia. And being part of a studio doesn't necessarily mean that they sign away their rights (in Colombia they're treated like independent contractors), it just means (in Colombian studios) that the studio takes a part of the tokens you make.
And for some people being part of a studio works on their behalf because the studio process the models' payments and that way they don't need to worry about the fees they need to pay to make an international wire transfer or whether they have the right type of bank account to receive international wire transfers.
I know of people in Colombia who are unable to get the type of bank account that would allow them to receive their payments so being an independent model might no be an option for them.