I never said there was problem keeping the sink clean, but I'll wager it's more work with a batch feed than with a switch. If nothing else, the mere act of picking up, inserting the cover, removing it and putting it back is more work than flipping a switch on and off. The way we use our disposal, which may be turned on more than once during a kitchen cleaning, a batch feed would be rather inconvenient.
However, I will disagree that the "point" of the batch feed style is prevent things from going down the drain. While it certainly serves that purpose, _all_ GD's have baffles of some type to prevent things from going down the drain. Of course, some are designed better than others.
The baffle for my old Kenmore was "permanently" installed between the sink and the drain collar. When it wore out and got soft, it required dropping the disposal, dismantling the collar, etc. For that reason, it stayed in place a bit longer than it should have. On the other hand, the one for my InSinkErator just sits inside the drain making R&R a simple operation. In the 5+ years that the InSinkErator has been installed, I have not had a single instance of something falling into the GD. The overlapping design of the rubber flaps prevents items from falling into the GD, yet allows water and small food pieces to flow right in.