I think "most" people understand what Beta means. As Chris says also GHL do not release software even in Beta form that is full of serious bugs, if you read the thread they are looking for input into fine tuning it and putting it through its paces.
As for people signing up, check the thread out, there seems to be many wishing to help GHL develop their software as always.
This is nothing new, GHL have used this path for over 5 years now and to amazing effect.
Lets not start a pointless debate over a positive request by GHL for users to help advance GHL further.