May I suggest the Control Block? It provides a nice and safe way to shut down the RPi and of course allows you to connect arcade controllers.
I actually bought that product and it would't work right. Plus it wasn't cheap.
Awhile back someone noticed the posted info had a typo in the info the company had posted.
I got no help from the sellers of the product.
Gave it away to someone to see if they could get anywhere with it.
So I wouldn't suggest that item, personally, unless you are a linux devvy type.