I recently bought that case also. I got three colours - stone, midnight blue, and saddle brown. All of my cases can wake the iPad when opened. You probably got a defective one.
The case is good for its purpose. Obviously its not the same quality as an official Apple case, but seeing as Apple do not have a smart case for the Mini4, this is a good substitute. The outside is fake leather, and the inside is microfibre lined. Holes line up OK but not perfect.
The volume buttons work fine on all three, but the power button on two of the cases wouldn't work at first. I had to soften and loosen the case a few times and then the power button would press OK.
I had an Air2 before replacing it with the mini4, and I had the official smart case for it. This replica for the mini4 is pretty close to that. Overall I'm happy with it and I think its much better than the offering that Apple sells.
If anyone wants photos of the midnight blue, and brown, I'll take some photos of those as well.