Are leather shoes good skate shoes?

No.

1. You want quality shoes that will endure wear and tear. Leather shoes degrade very fast in a skating environment.

2. Leather shoes vary on how comfortable they are as they can be designed for all sorts of things (formal wear etc). Skate shoes are designed to be used actively.

3. (Debatable) Leather is less of a breathing material. Meaning as you sweat up less air can escape or refresh your feet.