They have only just announced the beta will start soon. Only Sprint, T-Mobile and Samsung Unlocked are eligible. Still won't see a stable public release till 2020 for carriers.
Beta is full and I want it so bad. If anyone leaves give me a holler I'll gladly take that empty seat even if it's in the nose bleed section
I'm gonna say for 99.9999999% it's the beta program for the members app itself. The beta isn't live for anyone so its impossible thats it's full. Keep a look out here and remember only Sprint, T-Mobile and Unlocked are able to join once it launches.