Yes I think Priscila was on the card because she was Brazilian and it was in Brazil. It was an opportunity to showcase her talent. I believe her original opponent dropped out, I'm surprised the UFC put her in with someone as seasoned as Valentina.
It doesn't help that Yamasaki is Brazilian too. I think that influenced him and he felt the pressure not to stop the fight too early. Unfortunately it went the other way, he let it go on too long.