If there's a difference between catch wrestling and jiu jitsu, then I'm willing to bet the ability/willingness to move your ass is among the top candidates.
Jiu jitu is all about leverage. Just like judo. The maxim, position before submission, doesn't even tell the whole story. You could almost argue that in jiu jitsu, the position is the submission.
And the only way to achieve the "submission position" is to move your body. And the only way to move your body is to move your ass.
I haven't trained a day in catch wrestling. But I've got a lot of "wrestler" in my game. Sure, I've only got one year of high school wrestling under my belt. But even after a year and a half of training in jiu jitsu, the wrestler in me stands out like a red gi on a white belt.
That's no crime. There are plenty of guys with a lot of wrestling in their jiu jitsu who are nonetheless effective gi fighters. Leo Viera is the first one who comes to mind ...
But it shows up in my game in ways I don't especially like. It makes it easy for me to linger in side control instead of going for a real jiu jitsu "submission position" like knee on belly or that sort of reverse S-mount that happens right before dropping the far side armlock. It makes it easy for me to not move my hips to the side to better attack with armbars and triangles--short legs or not. And it is little surprise that after a year and a half, my best submission remains the keylock, a shoulder crank that doesn't require a lot of body position (i.e., somewhat position agnostic, you could say) in order to be effective.
That last bit about the keylock really defines catch wrestling for me, right or wrong. If I wanted to be a big meanie about it, then I'd say the spirit of catch wrestling boils down to "Just Grab Something and Twist."
But if becoming a catch wrestler is just a paving stone on my road to becoming a more complete jiu jitsu guy, then so be it.