Windwalker,
Speaking from my experience in the lineage, not necessarily of Yang Wenhu, who I've never met. The shenfa in the videos of his later years is exactly the same as the bigger shenfa used to build gongfu that's shown in the OP. Sometimes the bigger shenfa is used in application, but more often it's the smaller version. So yes, it can be used very quickly, but whether big or small, fast or slow, in my experience it's driven by the opponent's energy rather than somebody deciding to wind up and do-- whatever, as is usually shown in demonstrations involving visible shenfa and/or fajin. If the method is incomplete (including solo and partner work) or misunderstood, then of course it won't work as well as it might.
You yourself have posted videos of things that are not readily apparent from the outside to the uninitiated, so I'm not sure why you might expect that others' practices would be any different. And like your own shared videos, no one to my knowledge has been convinced of much of anything when viewing things they do not understand. For the most part, we all just talk a bunch of shit about things we know nothing of, and ignore the comments of those who have direct experience, assuming that their experiences are somehow lesser than our own.
The best we can hope for is to help an inquisitive mind start to understand that it's a big, wide world out there, and there "are more things in heaven and earth, Horatio, Than are dreamt of in your philosophy."