At the start of the video, you destructively subdivide the mesh. Is there a particular reason why you don't use the subdivision modifier here?
Not really, you could use the subdivision modifier all the same. I've just found that if you start with something like 5 or 6 subdivisions, it has to calculate that every time you update the modifier stack and it can slow things down.
But your mileage may vary of course, if it works, it works. ;)