If you consider going to a conference abroad like a mini-holiday with everything paid, and maybe even some fun activity, well, it can be seen as a reward.
Many big tech companies treat business trips as rewards. Fly business, live in a nice-ish hotel, get meals and taxi comped. It's a little vacation.
One of my early managers (based in Asia) saw his annual two-week business trip to the Bay Area as one of the most valuable perks of the job. He even brought his family along a few times (he paid for their travel obviously, but they probably shared his hotel rooms).