As one of the authors, I can tell you that Pijul development has never been as alive as today. It isn't public yet for a variety of reasons, but will be very soon.
Re:OpenJDK Migrates to GitHub
by OvidiusCicero on Tuesday August 04, 2020 @03:32PM
(#24053645)
May I suggest that you write something like that on the webpage? It looks really disappointing with the last activity from 2019 at the moment
As it stands, it's just a lot easier to use Git everywhere though, just so developers don't have to learn a new tool.
https://pijul.org/ is the only somewhat somewhat interesting alternative I know about, but it's implementation is in alpha territory, and development seems dead.