Honestly I don’t believe this is necessary because we don’t ever release beta versions of games. As was said above me, SG is pretty much in beta by name only. It’s unlikely we’d ever add an entire beta lobby because we simply wouldn’t offer many betas, if any. Nothing gets released until it’s ready so releasing game updates and things in beta would be pointless against just finishing and uploading them as normal. If we allowed you to beta things before they were done, you’d have a worse play experience than if you were a little more patient and let the Hive do its thing. It would also split players between beta and regular lobbies meaning there’ll be less players in both, especially at times when certain regions are quieter.
SG is in beta by name alone, really. Pretty sure I mentioned that in my earlier post.
As for the current TW one, I think this is the first time they’ve done a preview like this, or at least they don’t do them very often. Having a whole lobby for betas (as per this thread’s suggestion) still doesn’t seem particularly necessary when we can do what we’re doing with TW and just have a separate gamemode.