In order to have making money mean anything, CATE needs to be able to keep the money somewhere. The most straightforward way for this is some form of identity/password theft. She would hack a bunch of human's passwords, set up accounts they are unlikely to find, and use these for her transactions. She may have to move these about once/year as tax authorities will likely demand taxes on that time scale from the unwitting who've had their identities borrowed.

Just as Cate can steal identities to get money accounts, she can also get a fair amount of computing resources by stealing human identities of humans who are paying for resources. How many humans would know they were using 10% more than they actually needed or even 100% more?