alt Hacker NewsContrarian opinion, but being open here.
While there are exceptions, there's usually very little you'd get from in-person talks. And quite often, the people who are giving these talks are serial presenters - as a lifestyle, or sometimes career building.
But then like I said, there are exceptions. Especially when it's about something interesting being demoed for the first time, or a deeply technical conversation. Those are not the norm.
I think the missing condition here is "if you liked the talk". Not everyone likes or engages with the same material; I know folks who will effectively check out as soon as the conversation gets too techie, but they will happily sit through hours of (vacuous, to me) "life hacks" and pop-psychology talks.
I do agree that there are people for whom "the speaker circuit" is a job, and you can kinda smell it right from the presentation. But I think their numbers often depend on the type of event.