In the game of fastpitch coaches look for advantages, If a lady has speed but struggles at the plate or, is an average hitter its a no brainer to turn them around. you generally see better numbers.
Coaches next look to reduce strike outs by slapping and bunting. Not only does this make the D play with pressure it helps generate offence especially at the HS level and lower as additional bases happen with aggressive play.
I turned my DD around at 8 and she hit about 50% of the time on both sides of the plate up to 13U. After that she hit mostly on the right side especially in HS/College because the coaches liked the HR and she did not have speed.
With that said as a lefty while her power numbers SLG % were lower, her average and OBP was better as a lefty.