I really like the SW in that photo you linked, Una. But the thin sole and the suede are a recipe for salt damage

While brown suede can lean boho, I find a black suede to be much more elegant than leather, especially in an OTK boot. Something about leather always leans edgy, urban and slightly sexy, again, especially in an OTK boot. I think suede is easier to dress up or down, is normally softer and will almost always fit more closely than leather will.

I think suede reads dressier to me -- black suede, anyway. And there is that element of luxury. I'm sure it's historical, or class-related, or something like that, but, the idea that one can go about in these soft-surfaced shoes with the delicate nap connotes some type of indulgence or luxury, in comparison with people who required more rugged, waterproof footwear.
Of course, modern technology evens things out a little. And on the matter of the La Canadiennes, I recently ended up with a pair of the black suede, waterproof 'Calebs' which I intend to test drive in a Canadian Maritime winter...will keep you posted.
(long-time lurker; infrequent poster!)