Yup... with my
I2 it works in any mode when landed and props shutdown. When in the air, the camera is locked to aircraft forward view + tilt in follow mode, and will yaw & tilt in free mode. As soon as I switch from free to follow mode, the camera is reset to point forward, but the tilt amount isn't altered/reset.
As to why would I want to use a finger on screen... because then I can control camera yaw and tilt simultaneously in the same way as if using a 2nd remote... i.e. The camera can be moved diagonally instead of being limited to just one axis at a time when using the RC wheel and C buttons. As an example of where it could be used... in smoothly and accurately following a vehicle along a track which turns and climbs eg in an s shape. You can also speed up or slow down the rate of change by dragging your finger further or closer to the blue circle. Try it, it can be fun