^^^^* click for me as well . And like Crow it is part of my shot process .
I draw and come to anchor, I relax my release hand untill it comes to the click . Then I start looking at my intended target . I expand in the shot untill it fires while staring where I want to hit .
It really helps alot to keep your shot process the same , especially like Crow said in high pressure situations . Also it helps me when on unlevel terrain like uphill or downhill shots , it reassures me that my form and everything is correct during my process . So for me the click is needed when I'm shooting shots that aren't normal like out of a stand , uneven footing , uphill , downhill , etc.... It helps me alot .
Indoor I do not use a click because there aren't any of those crazy terrain changes .