OutdoorAppDeveloper
In general, invisible buttons are a poor UI decision. The reason is that it complicates the use of a device for new users and those with cognitive disabilities. My almost 90 year old mother would be at a complete loss when told to press the home button and there is no home button. A better way to go would be to have the ability to detect when the user's fingers are close to the button (proximity sensing) and then make the button visible so they can see what they are about to tap on.
