I think you are missing the point of the app. The cursor part of it is more of a gesture, or you can think of it as a "thumb extension". The point is to help you avoid the inconvenience and save time by allowing you to reach farther parts of your screen without repositioning your hand. I called it a "phone touchpad" just because, when you activate it, a part of the screen is acting like a touchpad. You are not using it for a specific purpose of having a cursor on your phone, the cursor is basically just the tip of your "virtual extended thumb". So it's a utility/accessibility software.
Using a physical mouse would be the opposite of what this app is trying to achieve.