While the idea of yodeck is great, most people looking for a raspberry pi videowall system are trying to find an alternative to other expensive videowall systems out there. It truly defeats the purpose of using extremely affordable equipment paired with a susbcription fee that would in the end turn out to be more expensive.
Imagine honda selling $100,000 car in order to be sustainable? Some might buy them if they can afford them, but Hondas were made for very specific market (the ones who couldn't afford a Mercedes).
Imagine how cool it would be to actually be able to provide customers an affordable way to build a crazy video wall. I would definitely be excited about that.
This is just my opinion maybe I am wrong.