I think it's something you need to experience to see the value in.
In fact, my impression actually turned around when the "bring your children" thing started to be normal. I vividly remember a few talks at DebConf where I was not able to follow the speaker because of verbal small children in the talk room. Since then, I really really prefer to listen to talk recordings at home.
is it really what GIMP needs though ?
It depends. For creating production-quality code certainly true.
But for design discussions, feature priotisation etc. an in person meeting often is better. Also such events /can/ lead to interesting results from hacking sessions where people collaboratively spin out ideas and code stuff. That code typically needs cleanup, but can spark ideas. Way home from a conference for me often was the time where I had creative new ideas :)