My persective is the opposite, probably because I'm a bad swimmer and a comparitively good cyclist.

My first triathlon, my swim was so bad, I was gasping for breath just to finish the swim.

Swimming is so technique dependent that if you're a poor swimmer you can make quantum improvements in time and energy expended if you can just improve your mechanics a bit.

Also being confident in your swimming from your training will help reduce wasting nervous energy. Thus I think it makes sense for first timers who aren't strong swimmers to overemphasize swim training, particularly working on technique.