Swimming is not a great anaerobic exercise as it only works a muscle through the positive not the negative, not sure what I mean?
If you stand in water and do a curl, friction is applied by the water, in the positive moment the bicep is working, in the negative portion the tripe is working.
Is swimming good for muscle growth? Not really
Is swimming good for joints, maybe, but that's what proper weight training is for.
Is swimming for for heart and lung health, now we are getting somewhere, but for effacy moving from one weight bearing exercise to another quickly for 15 to 30 minutes will garner better results.