I also think in terms of effort vs. reward, swimming is a tremendously worthwhile skill to learn. You can become reasonably competent at swimming in 40 hours. Compare that to learning a language, which can take 1000s of hours.
40 hours of flashcards and practice can cover maybe 90% of your typical tourist conversations for many languages. Where are you from? What is your name? What do you do? How much does it cost? Can you give me a discount?
I agree, if there is a life skill you need to have, it would be knowing how to swim.