"Aww. Don't worry, babe. I'm sure there's some nice, high-security vaults somewhere for you to break into. And, hey, if I don't get street-cred for having Black Maul for a girlfriend, maybe you can get street-cred because your boyfriend is officially a retired merchant of death. Infamy by association is still infamy." There's an odd logic there. Any criminal who did something for a while and then retired is probably pretty good at it. Street-cred is inevitable for that.
What's really odd is that Arthur seems to be encouraging Willow's supervillainess antics.