Plus you get to watch it in 9:16 portrait aspect ratio, just as Martin Scorsese intended.
I would imagine the reason nobody has sent any DACMA notices or stepped up enforcement yet is because this method of piracy is almost too stupid to take seriously.
I think such short clips curated, surfaced and demographic matched by the almighty, all-knowing algorithm could be considered as crowd-sourced movie trailers playing the role of modern day word of mouth. Just like google books search results are restricted to few relevant snippets / pages but not the whole book, similarly Tiktok can restrict sequentially watching a movie.