Jimmy's best skill is that he's completely ridiculous
I absolutely love that Jimmy's superpower is his ability to solve any problem with nothing but brute force and spite.
Currently rewatching and got to the episode after Jimmy messes with all of Chuck's Mesa Verde documents. Chuck figures out right away what happened, but it's absolutely insane for him to tell Kim, "Jimmy broke into my house and stole all my boxes of paperwork and brought them to a 24/7 copy shop where he copied and altered all the addresses using glue and an exacto knife, and then swapped them back a week later, so you should tell your client to fire you and hire me again." Because it would be absolutely insane for anyone to do that.
And like I feel kind of bad for Chuck in that scene (or would if he hadn't been such a piece of shit to Kim earlier) but it's AMAZING that Jimmy is so good at what he does purely because no reasonable person would put in his absurd level of effort.