It's because they have to communicate "sexy female" to the audience. I'm sure putting breasts on it - like in "Howard the Duck" - was also mentioned during a meeting. /s

I like this quote from "Solaris" (paraphrasing): "We leave behind home and family, and risk it all, to take off for the stars, looking for new strange worlds. But truth is, we're not looking for aliens, we're looking for mirrors."

Every time we have aliens and mythical creatures in a movie, they're just some mishmash of well familiar animals, and... us.

So no wonder they made dragons look like house cats hybridized with lizards, and then made the female exhibit features only typical of human females. I mean she almost wears make-up.