When you broadcast a TV series you get Nilson ratings.

When you run the a streaming service you get data on when people go and take a toilet break.

This is not very useful for already existing catalog, but when you write new content there will be pressure to adapt the material to the data and so all the new stuff ends up being bland and boring ("we get 3% more viewership if the leading lady is blond with shoulder length hair", means that every tv show will be blond festival).