Although it might be rationalized, it is still a lazy trope that undermines the notion that indigenous peoples may have their own creativity and achievements. It's a lazy and insulting practice.Tilly may be from a higher gravity world...
(Maybe the in universe excuse for the shift in her appearance has to do with her new job being set some place with a much lower gravity?)
...So she's three times stronger and faster the natives, or maybe her lungs haven't been shredded since birth by her birth planet turning to bullshit?