My take on swimming as it relates to conditioning for softball is that yes, it is advantageous. The overall physical shape required to be in for swimming competitively will definitely help your daughters athletic endeavors. It also should help reduce potential injuries. Will it replace certain softball related exercises? No, but they will have an edge over the kid that does nothing else IMHO.Any advantages to this type of conditioning in relation to softball? Curious to hear others' experiences.
My oldest DD swam in HS but never caught the softball bug. My twins (now in college) played just about everything else while focusing primarily on softball.