She should have gone with the convenience store. This is going to end badly.
Would do you prefer as a reader, Faye in another low end service job, or Faye doing welding for an underground robot fighting ring? Questionable Content could use a bit more awesome in it.
Even in-comic, doing something similar to Coffee of Doom would just lead to Faye getting into similar trouble, and it would delay the rest of her life even more. Like many characters in this comic, she needs change.
So, so so much. And I really don't think they are fight-for-your-life kind of robot fights - with AnthroPCs able and willing to change their chassis and being able to be uploaded to a computer, it seems more like boxing or wrestling to me. Without the threat of permanent injury. Or like the 'robot-fights' people are doing now, but with consenting AIs at the helm.
I think the reason they are illegal are different kind of rules - those that state that anthroPCs can't carry deadly weaponry or armour except if sanctioned or employed by governments or something. (For example, mercenaries or security companies that do have an official license to carry certain weapons might be able to acquire the same license for their Deathbots).
And it would be a well-paid, creative job for Faye, in which she could use and hone her skills - if somebody discovers her and hires her away, even better. (Another plus - she doesn't have to go through job listings, doesn't have to fake-smile at people and she can start working immediately)