Skills are like human-readable computer programs. I have one to do releases at work; how to get the canary approved (2 slack messages required), how to ensure that the rollout is happening, what to look for while the rollout is proceeding (any incidents opened during the rollout? error rate look good vs. the non-drained pods?) and then how to repeat that process for the next two tiers. It keeps a ticket updated with the current status so others can follow along and not wonder "is there a release going on?" "did we do a release yesterday?"

You could also write a computer program to do this, but because so much random special stuff can come up during a multi-hour release, it's sort of great to not have anything hard-coded and to let a frontier model be there to assist you when things are weird. (Weird things that have come up -- hung kustomization controllers, release freezes, etc. When Claude notices during the release, you can just get a ticket to go fix it. When you're doing it manually, it would probably be a half hour of investigating "why didn't our release go here?". Such a time saver and a safety net on risky rollouts.)

So that's the sort of thing I use Claude for. Things that are computer-program like, but ad-hoc enough to not really want to write a computer program for it.