New fuel line - benefits of a larger line?

There is a popular fuel line mod for the slant 6 that reroutes the supply line from pump to carb. Flexible neoprene is the easiest way to do that. Bending steel line isn't easy. Anyway...
If your OEM steel line from tank to pump is rusted away and you need new, 3/8 is probably close to the same cost as 5/16 so...
If there's nothing wrong with the OEM 5/16 tank to pump line, I would have to prove in inadequate for my engines need before I replaced it.