I was semi-considering using the board devlogs as maybe an early dev posting thing. Then maybe, once a project is further along, I'd use the project specific devlogs if I want to communicate any detailed news about something.
I tend to use project specific devlogs for things like notifying when I might take a hiatus, for things like either last minute editing, or if I might extend a project. (There was a time I'd write a lot of web serials.)