to what extent do we search out and describe glitches or irregularities for Aeria?
Betas vary from game-to-game and company to company. Some are little more then glorified adverts, while others actively encourage the players to contribute to the game's development.
SB is developed by a Korean company and has been out of beta there for several months now, so most of the game-play bugs have been ironed out or identified, and our capacity to request changes is very low. Aeria will probably only need us to point out localisation issues such as typos within NPC text and mismatched voices.
The other purpose of the beta is so Aeria can test out their server hardware and make sure it won't explode when large numbers of players log on or congregate in one area. For that, all they need us to do is just play, and get involved with any events they run.
Since your characters are (usually) deleted after a closed beta it's often good to just take it easy, learn the ins and outs of the game and decide what you want to do with your first Live character (class, faction, levelling strategy etc). Of course, Aeria would like some of it's users to achieve high levels so they can test that content, but it seems to take a few months to get maxed in Korea so I doubt we will see anyone get there in CBT.
I only have limited experience with Aeria's games, but Open Beta should effectively be the Live launch, when they will open the cash shop and no longer wipe all characters. The "beta" tag just stays there for a month or so to explain away the rough edges and as a warning that things could still go horribly, horribly wrong.