The best part of airgun competitions is spending time with other people that enjoy airguns. Just like any other subset of humanity, there's enough good ones in the mix to make some really good friends.
Rarely a day goes by that I'm not communicating with airgun buddies in some way or another. And all of those friends were made through airgun competitions. So it's not about proving anything to myself or others. The competition part is a fun challenge, but not the primary reason for going. The correct mindset to get the most out of it is to be rooting for your "opponent" cuz if you're doing it right, they're also your friends.
As for sponsorship, yes of course there are some people representing manufacturers or retailers, but I'm not aware of any of even those "sponsored shooters", who are getting their travel expenses paid for (gas, airline tickets, etc). From what I've been exposed to, I'd suspect those that have a free ride to attend competitions are extremely few and far between.
I've always paid my way to competitions, gas/food/pellets/scopes/air/entry fees/etc. Attending a field target match and camping with my boys for the weekend is a heck of a lot cheaper than getting sucked into some tourist trap type vacation. And MUCH more enjoyable.