raises the angle over the bridge
some believe that it improves the "feel" of the fretted strings
makes it softer
these people often believe that the tailpiece should be firmly against the body to increase tone and sustain
the raising the break angle does improve the "feel" of the fretted strings in my opinion
but I prefer to raise the stop bar
rather than overwrap the tailpiece
I only have one Gibson these days but it's a very nice ES-335. I don't top wrap the strings. Never have.
I do screw the tailpiece all the way down to increase the string angle as the strings cross the bridge. I feel it seats the strings more firmly against the bridge saddles.
Same idea as using a string retainer for the E and B strings on the peghead of a Strat to seat the strings more firmly against the nut so they don't buzz or pop out of the nut slots.