I think so. Most startups are not that impressive in their earliest days, and almost nobody is going to care if they even know you exist. Sooner or later you're going to reveal what you're doing and it's never going to be too late for your competitors to react if you actually get their attention at all.
On the other hand on a community like HN you can get lots of feedback, help and support by being open about what you're doing and what problems you're facing.
On the other hand on a community like HN you can get lots of feedback, help and support by being open about what you're doing and what problems you're facing.