Switch hitting doesn't have the same value in softball as it does in baseball.
I disagree for all the same reasons you already listed. That skill is an advantage in softball the same as in baseball - at least around here it is. Our area has some serious softball going on from youth through adults.
My right handed niece has mastered a killer left handed slap bunt so she can use her speed to get on base or advance others already on base. She had to really work at it, but I'm hoping DD7 will come at it more naturally.
I think what NSG is saying is that in softball, if you can bat left, then bat left all the time to gain those advantages. That suggestion assumes the player can drive the ball from the left side, though. A player who drives the ball from the right and slaps it from the left is tipping off the opponent to what's coming when they step into the batter's box.
Players gain an advantage by switching sides in baseball because of the way breaking balls break. A ball that curves towards you appears to hang in space, making it easy to see and hit. A ball that curves away has the opposite effect. Batting opposite the pitcher (right against lefty, left against righty) ensures that curve balls curve in.
There are no curve balls in softball.
