Great Article mate, while more I read more it makes me think about monero... I remember the 'Fungibility' term in the Mastering Monero book, and I would like to quote that section, because that's the way they worked around the 'Silent Payments':
Fungibility: The term fungibility refers to assets whose units are considered indistinguishable and interchangeable.. For example, imagine that you let your neighbor borrow 1 kilogram of flour for a cake. When they return flour the next week, of course it will be 1 kilogram of flour from a different source (since they used your original flour for baking). This is not a problem, since flour is fungible. However, vehicles are not fungible; if you let your neighbor borrow your car, you probably want the same one back!
In the case of Monero, its fungibility is a feature of its sophisticated privacy practices; the obfuscated transaction record obscures the history of all Monero. If you let your friend borrow 1 Monero, they can return any 1 Monero, since they're indistinguishable. This particular quality may seem like a minor nuance; however, fungibility is crucially necessary for most practical uses of any currency. This characteristic is absent from most cryptocurrencies, with transparent ledgers and trackable histories.
About this point:
6) No one, except for the sender of the transaction and its receiver, will know that the payment actually occurred.
I like the logic behind the 'Silent payments', but thinking about how the bitcoin blockchain should work with this idea makes my mind blows up.
Bitcoin blockchain was made to be public information, if we start obfuscating transactions then the community will divide, and then the fork will come. That's why I think these silent payments should be focused on a new coin and not be implemented in bitcoin.