As I understand it, the fine metal jagged business edge of the blade needs an estimated two days to “rest” after being shaved with and the ensuing stropping involved. The molecules can then “relax” to whatever position their atomic “memory” allows. Then when you next strop you can actually “comb” the metal shards into alignment without fighting the memory effect too. Hence, a sharper edge at use time.

Of course, using one blade for one day of the week just makes it easy to not mix up which one you used two days ago. Ego issues not withstanding and certainly valid.

And, if you are only using a blade once every seven days, you’ll go seven times as long between honing or sharpening needs.