I agreeI love it. That's a great idea to get kids and adults engaged with puppetry. I can still remember how excited I was when I got my first Fisher Price-produced Rowlf puppet. I can only imagine how I would have reacted back then if I had the option to design my own anything Muppet.
$100 may be a bit out of reach for the casual gift purchase, but that may actually be better in the long run. Hopefully the stock parts have decent material and build quality, and that they land on the waiting arms of those looking for a new (or better) way to express themselves to the world around them.