I love them because they are simple, classic, and not over-thought or elaborate like many shoes. In my opinion, shoes should be as basic as possible (I don't think there would be as much foot issues if people didn't rely so much on cushions and support... humans were meant to walk barefoot, after all).
They are completely flat inside, no arch support, and the thin soles wear out quickly. Not that that's a problem, because the thin canvas tops wear out quickly too. They are overpriced for what you get.