It helps with slowing down eating. Also I have a senior cat and a middle aged guy, it helps for arthritic pets- they don't have to bend down so far.
I've experimented with a few heights, and mine like the Our Pets Healthy Pet Diner
the best. It has a 4" height. I use the stainless bowls for dry food, but Corelle dessert bowls for wet. I bought mine at Kmart for a fraction of that price though. The Lola didn't like the 5" fancy wrought iron feeder I bought.
I think it was too tall. The 2-3" feeders aren't tall enough for my cats.