I don't think she's just taking money from The Mouse, she doesn't really need to at this point, unless she saved very poorly. TW is currently on everybody's list of "People I Want to Work With" in Hollywood and she seems very excited about that. That and the getting to play a female Thor/superhero and not just Dr. Jane Foster: Love Interest is probably a big draw as well. Not to mention potentially some of the more meaty emotional cancer scenes. I'm not a big Natalie fan and I don't think she sounded dismissive about the film, her tone was light and Jane becoming Thor is inherently a little silly as a plot point, even when done really well. I'm sure the film will be pretty different to the last time she played Jane in quite a dour film that was also more than a little silly. Even if she is just in it for the money, there are plenty of actors that most likely joined the MCU more for the name/visibility than the artistic merit and turned in good performances. I would imagine there has to be some sort of pathos, if they're using Jane's cancer battle and there was a mixture of comic dealing with it and real pain in Thor's IW/Endgame storyline.