
If you look closely at the white plastic disc you will see there is 5 openings, this is a clear indication that it is a restricting device. The main body has a larger chamber that regulates the opposing pressures to maintain balance, ie when the tank is near full and has the most pressure going into the charcoal canister. Then when the engine is sucking vacuum it regulates it going the opposite direction along with the orifice on top of the charcoal canister. the fiber collar attached to the bell chamber acts as a shock absorber to the action of the spring.
The filter element in the chamber of the clear fuel filter will do the same restrictions.
Both will reclog at some point, one you can see one you cannot.
Phew!
This is just my assumption