Well that sucks
All they’ve said regarding motivation for that change is that they are changing their API so that it “is aligned with our broader objectives”. It appears Netflix considers what films you’ve watched and what you thought of them as their data, not yours.
The first implication of these additions: if you decide you just want to create a “Netflix” app, and add significant value on top of the Netflix service, you cannot charge your users for that value. You can do something positive for Netflix, but not for yourself. There is no incentive for you to build something useful for Netflix customers, and if you’ve already built your app, you have three months left.