I thought this would be handy while I was making a maneuver node for a transfer to Duna and the encounter was located in the sun from my pov, so basically I saw nothing. Like the F2 and F4 modes which you can toggle, with this mode you can turn off all textures (and glare) off the sun and the planets. Then the only things you see are the orbital paths and the planet/ship/etc. A bit like when a planet is too far away and you see the round icon.