Just like HIVE, HiveFest means different things to different people... For devs, witnesses, it may be about showing what they are doing, but for regular peeps, it is an opportunity to meet your fellow Hivians IRL...
You are right that you can watch a presentation on YT from your home, but the real deal is behind the camera, on the streets, bars, beach, etc.. I do regret not going to KL this year as it was an opportunity to meet David, Cholocatescorpi, Macchiata, you... Locals from that part of the world...
On the other side, I have to be honest here and say that I like more "smaller" Hive meetups, like HiveBeeCon that we had in Poland 2 years ago, or BuzzParty meetups in Hamburg and Graz... Speaking of that, there will be another one next year in May... https://hiveopendays.com/