I disagree in that most hackathons aren't "hackathons". They're events where companies want you to use their product to "advertise" how awesome their product is

I disagree in that most hackathons aren't "hackathons". They're events where companies want you to use their product to "advertise" how awesome their product is to the community. Sure you learn things, but most of the shorter hackathons, you're learning very very shallow things that you didn't need to go to a hackathon to know.