I saw that in a catalog recently. Apparently it is designed as a conversation piece, and as one of the first SAK's that isnt really a useful tool. Makes about as much sense as the folding knives I've seen that are 20" long (when open)
Yep, that's pretty much the idea. It's not only a sales tool but shows off what they are capable of making. SAK's are an icon not only because of the quality for the price but for the options and versatility they afford the user for knives in all sizes (well, not as large as that one, but...). This showpiece demonstrates that.
There were knives similar to this made a century or more ago. Those were handmade and required a very skilled craftsman. They were more works of art than anything else and highly collectible.
That's not a Katana and such swords (nodachi is I guess what that's supposed to be) traditionally had very practical uses. Though that ebay one is a piece of garbage not fit to cut weeds with nor safe to swing around.