The 2D display is an ID plotter. As such, it has no ability to distinguish between nonferrous trash and treasure, any better than tones and/or TID. In fact, it's easily argued that the 2D screen is less accurate on all nonferrous targets than tones and/or TID.
A main issue with air tests and TID, is that tester typically swings the object at a certain distance away from the coil, and with the object facing "flat" towards the coil. In the ground, if the object is closer or further to the coil, or the object is not lying flat (most won't be lying flat), then the TID will be very different.
I can see notching out high conductors if the beach is full of clad coins, for the reasons others have stated. BUT, if one is looking for gold, then notching out anything below zinc is a big mistake IMO. Granted, the reply to that would be, "If I don't try to notch out some foil or tabs, then I would be constantly digging foil and tabs". Well ya, that's the way it is unless one is hunting in the water.