I mean it’s fine, use whatever your comfortable with and Bluesky is the next frontier for development ideas.
EDIT: Ask five people you know outside of tech if they have a Github account. Everyone I know outside of tech moved to Bluesky from Twitter. No one I know outside of tech has a Github account. If I encounter someone who has neither, I'm of course going to recommend a Bluesky account from a utility perspective, as they're likely never going to contribute code, issues, discussion on GH if not a tech person. (most of my network is non tech, non startup, non SV people, ymmv; HN is the closest I get to tech folks most of the time)
And even then while "daily active likers" is down half from 6 months ago, it's still up substantially from even just a month or two prior to that. Bluesky exploded in size at the start of the year and it seems to be finally settling into a steady state with gradual growth (vs the prior explosive growth + falloff).
"Daily records" (at the bottom of the page) is a bit better metric of overall network activity and even though it has also fallen since peak it shows there's still an order of magnitude more activity on network than prior to blowing up.