I'm not sure it functions more then looking nice?
It's well made, fits like a glove. I thought it would help keep condensation down in warm weather use but it's winter now and I won't have that question answered for awhile. But, there was a bit of info included with the cover that mentioned removing it to dry any condensation. Hmmm.
Be very careful putting it on, don't pull it up with the handle cut-outs (which seems like a natural grab hold), I got two small tears in the fabric quite easily.