I have 2 children, now 5 & 2. My daughter was our first, so I did everything by the book, but she had a lot of spitting up issues and I was scared she'd choke lying on her back so I used the wedge to keep her on her side. My daughter loved to be cuddled, until she got mobile, so she loved the wedge. I think it was comforting and felt safe to her.
With my son (the "belly baby"), I found he would get mad at the wedge because he couldn't turn over onto his belly! I guess if your son is like mine was, very active and can easily move his head on his own, then he would probably enjoy having his belly time and sleep better.
Each child is different, good luck finding what works for your little "turkey foot" :) A.