Earlier quoted context omitted.
If you rotated the secret, why do anything else? I don't think there is any potential further damage (except maybe reputational).
1. Not all secrets can be rotated. E.g. I can't just "rotate" my home address, which I prefer to be private. 2. Even for rotatable secrets, "I don't think there is any potential further damage" rests on the assumption that the secret is 100% invalidated everywhere. What if there are obscure and/or neglected systems, possibly outside of your control, that still accept that secret? No system is bug-free. If I can take…
If it's not possible to invalidate your compromised software secrets, I would argue that you have bigger and more urgent problems to fix. But fair enough: Deleting them from GitHub might reduce the impact in such cases.