She wasn't really "world famous" in the way Giulia or Stephanie Vaquer were before coming to WWE. They both had legitimate established careers in Japan and Mexico with promotions like Stardom and CMLL and both have worked for quite a while.
Delta/Zaria has only been wrestling for about four years and mostly on the Australian indies. She got hired based on a WWE tryout in Australia, not because she was a big time established free agent.