AFAIK Autosave works invisibly in the background. The only time you will be aware of it is when you restart after a Logic crash. You will be prompted to decide if you want Logic to re-open your crashed project from the most recent autosave (which will likely be just minutes before the crash) or your last saved version. Which is, of course, whenever you last saved it before the crash.
I think it's a brilliant system actually. It's the best of both worlds. Control for the user to decide what and when to save. And insurance in case of a crash.
I know that I often use the ability to manually save or not save when experimenting. For example if I want to take a chance and try something wild that I'm not sure will work or not, I often save first, perform the experimenting, and then decide if I like it and will save again, or use the revert to save command to return to the previously saved state.
Thankfully autosave doesn't interfere with that sort of freedom.