I've consumed content from three virtual conferences this summer. They've all had more or less the same format: one or more tracks of prerecorded videos with simultaneous live chat with the presenters in attendance. One event had a livestreaming DJ as a kind of afterparty.<p>In my experience, there has not been any difference between "attending" an event and just watching the videos later. I have not been able to capture any of the benefits of actually attending an IRL event.<p>Granted, I've also avoided the indignities of IRL events, such as annoying audience members, long lines for conference food, and talks that turn out to be less relevant than anticipated.<p>I think tech communities have lost enough aspects of IRL events that there's nothing left to lose if you just allowed people to post talks throughout the year to YouTube under some tag and maybe applying light vetting for quality.
I watched quite a few live sessions of MS Build this year and I really enjoyed it. My employer encouraged this during the day and I learned a lot. If not for that conference being virtual, I would not have gone. I do think you miss out on the social experience/networking, but I'd be happy to see this type of thing happen occasionally going forward.