Why? Why would you want more than half of the memory on the server to go completely to waste? Why would you want to cripple SQL by limiting its memory that much?

Sure, that's going to reduce the % memory used but it's counterproductive. Free memory is memory not being used, it's memory going to waste, it's a waste of money spent on that memory. By doing that you will have around 16GB memory doing absolutely nothing, may as well remove that 16GB from the server and throw it away as that's the equivalent of what's been done there.