With your top hand in this position you are unable to move your hands freely across your body. This is bad as it DRASTICALLY reduces the effective area of control you will have when stickhandling.

You want your top hand extended out from your body so that there is a gap between your hands and your stomach. This will allow you to move both hands quickly and freely from side to side.

If you are used to keeping your top hand next to your hip this will feel weird at first, and you will probably feel like you have less control and comfort with the puck. Keep with it, make sure that there is the gap for your hands to move around and you will quickly forget that you could ever handle a puck/ ball in a different way!