alt Hacker News> people whose circumstances lead them to not wanting to spend much time at home, for one reason or another. At that point it's like a job with 30% travel: You either have few attachments, or are trying to avoid the ones you have.
Or a couple loves to travel and conferences are a good excuse.
In semi-retirement, I very selectively pick a few conferences to travel to in locations I want to be, at appropriate times of year, in interesting venues. Definitely less than I used to do.