At least by NASA, spring washers have been declared mostly useless. I'm not an expert on bolt fasteners, but I personally haven't seen a spring washer in quite a while.
So I guess she just knows her washers and doesn't care about the functionless ones.
Spring washers, aka lock washers, are useful for low torque settings on small diameter all threads when fastening with a nut; it gives a nice visual of when the nut is secured by ways of the lock washer. Or for visual inspection of battery terminals for UPS systems.
