Interesting tool. I could see that being used for making unique drawer fronts or box lids. Not sure why this was done on 2" thick piece of wood though...a test, or maybe with the intent of resawing the sculpted layer off to create a grain-matched one from the remainder of the stock...

I've seen a similar kind of router jig used to rough out wooden spoon blanks, and in conjunction with some sort of indexing setup it could make some quite amazing spindles for chairs or railings that would be difficult to make in any other fashion.