It’s also full of “networking opportunities”, i.e. you spot the people that you usually only see at conferences, check in on them and then proceed to not even think about them until the next conference. As a bonus, you can also have conversations with new people who are going to ignore your follow-up emails!

Free swag, free food.

Last defense contractors expo I went to (for free) they had yo-yos, rubicks cubes, vacuum flask water bottles and lanyards. I took a bunch and sold them for a dollar each at the local swapmeet.

I kept the 3D printed metal submarine keychain though.