I really like the interaction with people over chats, slack and the club. I really feel closer that in some in person conferences. Many more questions from the audience answered too.
Also, living in a place where no many conferences happen, having the opportunity to connect to an online conference from home, for a price I can afford, not needing to pay the trip, the hotel, etc. is really good. I don´t even needed to ask for support from my company. To be honest, I always wanted to go to a Test Bash but, due to the costs, it was not possible.
On the other side, for the speakers (having some experience too) it has to be really weird to don´t have the feedback on live time from the audience.