Yes, most of the current JVC models will do CIH without the need for a lens using the zoom feature. So long as the throw distance allows it, this means you simply zoom the 16:9 image out to fill the 2.35:1 screen. When doing this without an anamorphic lens the black bars at the top and bottom of the screen will still actually be projected, they just fall off the screen. Because the JVC's have such good black this usually isn't much of an issue.
As to the question of why some still choose to use a lens with the JVC, it's because of those black bars. Without a lens a 16:9 image is still being projected, not a true 2.35:1 image. By using an anamorphic lens you "gain" the extra pixels and lumens that those black bars otherwise consume. This results in roughly 1/3 more pixels being used in the image and brightness increases as well (not sure if it's a full 1/3). If you are trying to fill a very large 2.35:1 screen, or have a lower gain screen those extra lumens can be important to maintain brightness. Others, I'm sure, choose not to sacrifice the pixel resolution.
For reference I use an X30 on a 120" 2.35:1 screen (1.4 gain) at a throw of about 15'. i have about 250Hrs on the bulb and I can still keep the aperture at around -7 in low lamp mode. My room is not a bat cave. To be fair though I haven't checked that this is truly enough lumens to be at 12-14 fl at the screen but it is bright enough for me.