I do a rough mix of the levels, and I set the 'init song with this position' for each fader on each track. Say at the beginning of my mixing stage I have 16 tracks. Having knobs initialised with a certain value, without knowing how to remove that initialisation, can be annoying.
It behaves like an automation snapshot that remembers that value without writing automation data on that control. This is where the 'Init song with this position' comes in very handy. However, if that control has no automation set, that value would be lost and I would not be able to know what it was originally set at. If that control has recorded automation, there would be no problem with this since during playback automation will automatically get the control back to the correct values. I may actually mess up the value if I accidentally bump on my physical sliders positions (or someone changed the slider positions while I am away from my computer for a while). The most helpful situation for me, would be when I am going to use a physical controller's slider (Korg NanoKontrol2 for me) to affect the values of a FL Studio knob for example. I can think of many uses for this feature.
