The pumps are simply turned off to prolong the part life span. Though many don't like it because they are doing a walk around with unpressurised systems.
As for the Speeds and the Trim can only imagine it's to reduce the work load in an other critical phase of flight: Taxi. You an I know it's not gonna make much difference but in a board room deciding these things it was prob. one guys little thing. I must admit I still did it when I was still flying standard boeing sop's.
