This seems like overkill to me, but Lamont is speaking very highly of this method. I personally rewatch movies extremely rarely, and the number of movies that I have seen more than once is very small, so the idea of watching one movie 50 times is rather nauseating.
I do, however, concur that re-consuming A/V media in an L2 is beneficial to me, as I noticed that I tend to struggle with correctly interpreting grammar the first time around.
I think I might give it a go for a movie 10x. I have about 1600 hours until fairly okay fluency aparently so 10-20 hours wouldn’t be too much out of that time. I may have to mix in other content while I do that though haha.