Building in public helps clarify your thoughts
An unexpected benefit I found of building in public is putting extra thought into my plans, actions and decisions. Even though I made lots of notes wrote a lot anyway it was never meant for anyone to read so it didn't matter. At times I think this lead to more emotional decisions.
Posting updates publicly made me think twice about what I was putting out there, against my name and if it was really the best decision.
It certainly forces you to explain the path you’re taking out in the open, which is probably a good thing for many hackers. Where it falls down for me is if your product development really suffers because you’re spending so much time tweeting tripe.