Its cardio, and cardio is good for everyone no matter whether its for losing weight or generally. Cardiovascular exercise uses all the major muscle groups of the arms, trunk and legs. Any cardio can help with weight loss in a sense because your burning more than your consuming but mostly helps to make you a stronger and fitter person. You get better strength and endurance from swimming and you get fitter by the day. And also I think its a fun form of sport! Its better to move than to do none at all!
- Sam