I do not have 2d capabilities in my bow unit. I have my DI unit mounted on the TM. I have/do use the DI image while in a more or less stationary position, for vertical presentations, but with the idea/fact in mind that I'm going to be seeing horizontally stretched out images of cover (much the same as what I'm used to seeing with 2d, while stationary).
Now, I will have to quantify the fact that I'm used to a 20deg cone angle in previous 2d units. And in the normally less than 25 fow that I'm used to fishing, a 20deg cone only covers ~8ft diameter circle of bottom ... & progressively less diameter of water column from bottom to transducer. My DI unit's "angle", though only 6deg "thick", is 45/75deg wide (depending on using 455 or 800kHz setting). And, of course, I can split the screen between the two settings.

Consider, too, that I skipped past a large portion of the technological changes in depth finders ... skipping over the dual frequency 2d, color 2d, etc. and went from a series of low end b/w 2d depthfinders to a DI unit with GPS, mapping, water temp, waypoint marking, speed registering, color imaging capabilities, which can be customized to my preferences. I will also admit that I bought the unit primarily for those capabilities, as much as or moreso than for the DI image capabilities. I've just learned to admire the DI images, over the pixel blob images of 2d, as they take a lot less "interpretation" (or experience) to understand what's being shown. I'm still in the newbie learning phase of DI, so I'm hoping to continue to get better at using its capabilities.

... cp