Joe Davis said to stick your bridge arm out as far as it will go, then stick it farther!English billiards player Jack Karnehm used to advocate a straight bridge-arm so that you had as much cue in front of the eyes as possible. I don't think he would have advocated a long stroke to squeeze a little more out of it though.
It does help you to see the shot better. A bunch of us started gambling with one hand on 6x12s in the 80s.
We all found that thin cut safeties from the end rail could be seen better shooting one hand...perspective.
But John Spencer took the snooker world by storm in the 60s....using a bent arm bridge and a long stroke.