> Sending two people and having them paraphrase the talks they saw based on the partial notes they took doesn't exactly sound like an efficient process.

Don't think of it as education. Think of it as spies debriefing the station crew at the embassy.

This is the right way to think about it. The talks are probably recorded anyway. Really, you want to get some people to go out, see how others are doing things and solving problems, and bringing back the parts that are relevant to your current problems ("Oh, this guy solved problem X, which is really similar to what Ted was stuck on when we left!")

I mean, if I'm thinking about it that way, why am I sending developers on a spy mission?

I'm not sure developers are naturally skilled at parsing presentations (done by other developers, who also often aren't fantastic presenters) into meaningful presentations to give back in the office. Not that conferences aren't worth it, I'm just not sure they're worth it for that.