[majormajor]

Craftsmen absolutely think about what's stronger and more durable, not just what's nicest looking (especially for non-visible parts!). I've got a few pieces of pretty decent antique furniture that's made its way down to me in my family (stuff made by craftsmen, not by mass production), and the hidden pieces aren't finished or styled to the same degree as the front ones. The purpose of the back and other non-visible parts is to hold stuff together, not to look nice. I would also point out, from your own link, the specs for their "the ledge":

"available with a solid domestic walnut top, sides and doors with a plywood bottom and low voc finish or painted mdf."

(Of course, these little details about what's "the right way to do it" are rather irrelevant to the greater point, which is that if you're the type to want to do things the right way, you're going to do things that way. Just don't hate on plywood, it has its uses (and feel free to come up with the programming equivalent!))

Edit -- some more notes on plywood: a sizable piece of plywood (like for the back of a chest of drawers or bookshelf) is going to be stronger (especially with regard to bending, IIRC) and vastly cheaper than a solid piece of wood since it only needs thin pieces of veneer with good grain for the outer layers. And IMO, it looks nicer than having several individual solid-wood boards jointed together in parallel.

[jonah]

It's pretty universal.

We have some amazing antique Persian and Korean chests in the house. Hand carved and split grain matched fronts and maybe sides, but the backs are plain and/or rough hewn. These pre-date plywood, but the same goes - don't waste effort on parts that will never be seen, just build them to do their job.