Recently I came across a post on Reddit asking what "crushing to black" meant in reference to black and white photography. So, without further ado:
You don't always have to maintain full dynamic range across all the tones in your photographs, and sometimes clipping values will help clarify the subject.
There's often a focus on (I might even go so far as to call it a fear of) clipping values on the histogram. People will often critique with "you've lost detail in your highlights/ shadows" and while sometimes that's a problem, it's often the intent.