Inline Fuel Filter

I have searched info reagarding the in-line fuel filter from the pump to carb on a 1974 6cyl 258. It is either two port or three port.
What is the advantage / disadvantage with the return to the tank out of the third port of an in-line filter?

 

Fuel circulation is said to keep the fuel cooler and help prevent vapor lock. No real disadvantage other than added complexity. It's a very simple system. There is an orifice in the filter that limits the amount of fuel returning to the tank. The third nipple goes at 12 o'clock on the carburetor side.

It's described in the TSM, maybe not for '74. https://oljeep.com/gw/77_tsm/07 1977 4-Fuel-Carburetion.pdf Page 4-4.