I don't know if there is any benefit, but in the bad ol' days I don't suppose people were bothered with collecting all the nice makes and probably just wanted a decent shave. So a 7 day set of good razors was the business back then.
I think people chase them these days because it's lovely to see something old that is obviously meant to be together, still together.
I'd love a seven day set, even though I doubt I'd use it as it was intended