So the fed's interest they receive goes to the treasury I'm guessing? And the treasury pays interest to the fed?
This all sounds like installing a fan on a sailboat to blow it across the ocean
The fed is attempting to lower the availability of two asset classes (treasuries and agency RMBS) from the market so people either bid those lower, or move onto other asset classes which are then bid lower. Ultimately the interest rates for all assets are lowered.
This affects all sorts of things. For example, the interest rate on a prime auto loan securitization may be swaps + 50 across the entire structure, or maybe 2%. That allows the auto manufacturers to offer cheaper subvention (lower than market rates) or just low rates in general to the public, increasing the availability and affordability of vehicles.
The same goes for leasing companies which lease copiers, scanners, computers, and other business essential machines to companies. They are able to lower lease rates to small businesses.
Apply this across the entire economy.