This button on the remote determines whether the remote's cursor
buttons respond as a joystick or as a mouse.  This is not necessary on
the Amiga + A570: to enter joystick mode, the user simply plugs a
joystick into the Amiga.  To enter mouse mode, he uses his mouse.

Some CDTV applications only support one mode or the other.  Titles
should support both modes, if possible.  If a title only supports
joystick mode and the title cannot be reasonably controlled from the
keyboard, you should indicate this on your packaging, as an Amiga +
A570 user might not have a joystick.