If you turn the RTS (Humminbird) then you can see real time in 2D, just like a flasher.
my experience has been that it's a pretty narrow slice your seeing, so you better be good at the other scanning available. The value is seeing the reactions of the fish once you find them. It isn't a silver bullet, but a an addition to the tools that are already there: GPS, 2D, SI, DI.