When your entire hacking operation depends on someone who's really good at... having a CPU? The beautiful absurdity here is that "mad skills with a CPU" is like saying "mad skills with oxygen" or "mad skills with electricity." Every computer has a CPU - it's literally the Central Processing Unit that makes the computer, well, compute. The joke hits different when you realize the writers probably meant GPU (for rendering/processing power), or maybe skills with assembly/low-level programming, or literally anything more specific than "the thing that exists in every computer since the 1970s." It's like a chef saying "we need someone with mad skills with a kitchen" instead of "mad skills with a knife" or "mad skills with French cuisine." But hey, when your computer isn't powerful enough to upload a bad boy to the foundation's server, you definitely need someone who knows that the CPU goes brrrrr.