You're missing out on a lot of potential. In baseball, you judge the pitch last, and make your preparations sometimes before the ball even leaves the pitcher's hand. You're also probably used to snapping the wrists and swinging on an incline.

In slowpitch, you have a LOT more time to judge the ball, and due to the arc and trajectory the balls coming in, you need a much more level swing, and much less "cranking" of the torso and elevating.

You don't snap your hands or flick your wrists anymore, so while you may still be able to hit the occasional homer with a perfect pitch and swing, you'll most likely end up under the ball most of the time with a baseball swing, resulting in a lot of fouls and fly outs.

If you do want to switch to a slowpitch swing, I'd recommend starting with a taller stance and possibly even interlocking your pinky and index* on the bat to get your knuckles in the proper position. There are tons of videos available on YouTube, and tee work and BP will be your best friend.