Sole stitching done well is something that looks lovely, even more so if contrasting, so of course two rows of nice contrasting sole stitching looks marvellous. No wonder this became a thing on the posh spade sole shoes during the first half of the 1900’s. As often is the case though, the reason this type of construction appeared was from the beginning solely practical.
This picture here, which is of an Ace of Spades shoe that mimics the style from the 1930’s and 40’s, is good to highlight these practical reasons. Cause the two row stitching was from the beginning done when one did so called HAF soles, where the waist is single but front part double. So one row of stitching attach the welt with the first half midsole, then second row includes also the outer full sole. When you’re only after an as strong construction as possible, and price isn’t as important as it is nowadays, this was obviously super. And you could still make a rather sleek comfy shoe. Then this was aesthetically developed into the very characteristic spade sole style.