To me, this is a very simple technique and I have never had any doubt about it's usefulness in my bag o' tricks. Drills can appear and even be, very contrived and seem unrealistic. Sometimes they are, but sometimes, they're just a learning mechanism. If we insist on arguing about these things, I think it's an important distinction if we're arguing about the technique, the drill, the person in the video, or even something broader.
In practice, this technique is not really an outlier in the system(s), your elbow is in and down, you take center with forward intent and either bridge/intercept with something along the way or continue into a strike because center was open. The end. There are a great many hands in Wing Chun that work in fundamentally the same way, each maybe better in some circumstances than others, but they are all tools at the disposal of the practitioner.
The notion of reasoning or engineering your way through an assault is misguided, whether you're talking about this hand or another one. It all comes down to flow, just like it does in any effective system. These are our tools and I have always really liked this one, though I didn't have a Chinese name for it other than Biu Sao. As for moving from inside to outside, that's really a different consideration than whether this hand is legit or not. In my worldview it is and I've used it in drills not dis-similar to these and also training with non-compliant opponents. It flows very well sometimes, when it doesn't, I don't assume it's the technique's fault, that's just something that happens in training.