that is just to temporarily clean the pickup. If you have that black carbony sludge, it will break off in small chunks from inside the engine and while some will plug up the screen and restrict oil flow, some will get past the screen and those teeny small particles of sludge will accumulate and quite possibly build up in the clearances of the oil pump rotors, eventually stopping the rotors and shearing the oil pump drive or cracking/splitting/stripping the internal hex of the rotor. Don't ask me how I know this.
