I've lost count of how many times someone's offhand comment at a conference fixed a problem I'd been stuck on for a week.
That's the real reason I keep showing up: KubeCon + CloudNativeCon India, AWS Summit Bengaluru, Google I/O Connect, Datadog Live, GitHub Constellation. Not for the swag (okay, partly for the swag), but because hallway conversations compress months of "what are real teams actually doing" into an afternoon. Documentation tells you how a tool works. People tell you when it breaks.
Hackathons do something different: they force me to ship under a deadline with strangers. At the TON Blockchain Bangalore Bootcamp, my team built TON Scholar, a DApp, in one sprint, and it won a challenge prize. I learned more about scoping ruthlessly in that weekend than in months of solo building.
I also give back where I can: Snowflake Squad Member, Google Cloud Arcade Facilitator, Campus Ambassador for E-Cell IIT Bombay, and contributing during GirlScript Summer of Code and Hacktoberfest. Facilitating is selfishly useful too. Nothing exposes the gaps in your understanding faster than someone asking you a basic question you can't answer cleanly.
If you're early in your career and on the fence about going to these things: go. Stand in the hallway. Ask people what broke in production last month. That conversation is the conference.