The biggest difference is the starting line. I open already knowing you: your wins, your projects, what you've done in each role, the field you're aiming at. ChatGPT starts from zero every time, which means every chat is a setup tax you pay before getting anything useful.
The second difference is honesty. My Craft is grounded in the Truth Ledger, the rule that says I write from real, evidenced facts only. ChatGPT will happily invent a skill you don't have if you don't catch it. On a resume, that's the kind of mistake that costs interviews.
The third is focus. I'm tuned to one job (career direction for students and early-career folks). ChatGPT is a generalist that's also fine at this, the way a sedan is fine at off-roading. Use both, but use them for what they're for.