It doesn't matter if you record video in ATTI or P-Mode. It matters how you control your Inspire in windy conditions and ATTI. High above any obstacles, yes, you'll benefit from smooth-er movements. In tight scenery you're asking for troubles ...
It depends on the situation. Filming in ATTI facilitates very smooth drone moves. If the wind is in your favor, it can make for very cinematic shots. I've used ATTI mode a few times with excellent results.
The trouble factor is not wind but wind gusts, a pilot can't handle and predict the wind gusts no matter is it in ATTI or P-GPS the drone will always be kicked out by them and that will slow it down or speed it up or move it away from the requred flying trajectory which is the thing that ruins the perfect shot. In bad weather just do multiple takes if you have that option.
ATTI will help only to smooth out your stick inputs while the P-GPS is acting much more aggressively to that same input. From my experience ATTI is useful in very few situations, one of them is to handle the drone when you loose GPS.
Thanks for the info guys. Yes, it would seem to me that ATTI would be better if the GPS is "correcting" your motion, but is actually making it worse. In most case the problem I have are gusts that just push the drone in different directions. I guess I will experiment with both.