Wow.....excuse the applicative pun, but different STROKES for different folks!!! I suppose it all goes back to "find what works for you".
For me, swimming my long-haul (2-3 miles) is almost unbearable w/o music. I don't feel the music takes anything away from my workout, it only enhances it. I believe it's been well established that good music (music you enjoy and "feel") can diminished perceived exertion by as much as 30%. I believe there is some benefit in this regard...there have been many times my brain just clicks with the beat and I end up putting-out more power/energy without realizing how my HR is way the heck up. I've met many swimmer who equally love it.....and a few who didn't (enter Sparrow). Without the music, all I have is the monotonous sound of my breathing & bubbles...then my mind picks a song or beat and I keep repeating it. Like I said, to each their own.
Some people in the pool are blown-away when they see music while swimming...but it's become more and more common-place. The thing is, you have to get good earphones that work for you.
Hey, I'm not reviewing products, just concepts (music while swimming). One thing I will never give up though...music while on the bike.
Onto more pertinent issues....
I've not done a triathlon yet...how far do they usually swim and is swimming always the first event???????
Since most people can only sprint-swim about 200-meters, I'd imagine swimming a mile would not involve going full-throttle the whole time. How do you approach it? Like marathon runners, they dont' bolt out of the starting-block at full-speed, they just get into their pace. How do you pace a mile+ swim??? I'm guessing the fastest speed you can continuously maintain?
Also, I presume you swim free-style the whole distance?? Are you takin a breath on the right-side, then do a left, right and then breath on the 3rd stroke on the left? (alternating sides???).
If someone else passes you, do you feel compelled to keep up or figure you're losing?