That's a really interesting point. Maybe "hobby project" wasn't the best word choice. I just wanted to emphasize that I'm not looking for rocket-ship growth (or even money), just a way to slowly get users who will find use in my app.
You can be very serious about something while not striving for rocket ship growth. "Hobby" makes it sound like you'd have no qualms shutting it down with a moment's notice which prospective customers can frequently detect and is obviously not compelling.