I work in a pretty bright office -- usually I have the windows open and the overhead light on. My monitors (a Planar and a Philips) are both plenty bright enough for this use case, but neither of them will get as dim as I'd prefer once it's dark out and I have only the overhead light. If I would prefer to work by lamplight only (as I sometimes do), the contrast between the super-bright-on-the-dimmest-setting monitors and all the peripheral space around them makes my eyes hurt.

And, here's the thing: I like brightness, usually. As @ianai mentions, what's needed is a larger range, not the same range but brighter.