Interesting thought Elie. Why would there be a beta? I thought the whole premise behind going to Creative Cloud was to get updates and new features out quicker/easier. It would seem that there would not be a need for a beta version if you're only doing incremental updates.
Except you still cant release very untested software to paying customers. Many photographers may prefer to stay with the stable build during the beta period. There is always the possibility that the beta would break your catalogue entirely.
I could see adobe only offering the beta to cloud subscribers as a perk, but still calling it a beta. However, one if the advantages to a beta is to get current users to try out the new features (as there inevitably are in full number releases) and get dependent on them. This improves conversion rate. LR5 works fine for me. If I dont get to try out a beta, I am unlikely to upgrade until forced to by the need for camera raw compatibility with a new camera.