"I don't know [if I can save the world]. Maybe not. But I'm gonna give it a shot." (9.141)
Even when something is against all odds, Art3mis gives it a try. She's also talking about the real world—planet Earth—not the OASIS, which is the only world Wade is concerned with.
"If I win [...] I'm going to make sure everyone on this planet has enough to eat. Once we tackle world hunger, then we can figure out how to fix the environment and solve the energy crisis." (9.137)
In a world where people would rather spend money on digital clothing and gas for their spaceships, we're not sure they deserve a savior like Art3mis, but at least her heart is in the right place.
"It's not about the money. It's about what I could do with it." (18.69)
Art3mis's goals are a little more long-sighted than just making bank. She's setting goals beyond that, imagining what she can do with the money to heal the world. Of course, it all depends on her winning the money. What would her goals be if she lost? How would she have handled that monkey wrench?