This will probably sound crazy but does anyone orchestrate meltano using Github Workflows?

yes, and you're not crazy! Gitlab and Github I do all the time 😄

Are there any footguns I need to watch out for? Context is I have a pretty simple extract/load job I want to run nightly and have used Github Workflows in the past as a free cron service.

yes, but it depends on what exactly you're doing Generally just go for it, the footguns aren't that bad

Been doing it for a while 🙂 https://github.com/edgarrmondragon/meltano-dogfood/