Its nice to see that someone here didn't misinterpret what I was saying. Not only do I think that this drill is a great exercise, I also think that moving images says more than any written word on this forum sometimes! And that is why I respect anyone who shares footage like you have here.
And I agree here too. Although, me being me, I will replace 'chisau' with 'interactive training'! For me, Chisau is a manipulation tool. It's there to help us teach and also to help us understand how to shut down an offensive or incorrect method 'instantly' upon contact.
Fighting from outside the chisau paradigm is called Gorsau from my limited memory, and not many Wing Chun clubs do this often unless they're into sparring or competition. Not my cup of tea, but something I can coach through various interactive programs. For the right person