Swimming in sleeves is banned by ITU rules on everything shorter than medium and long course triathlon (half and full IM distance). Mostly it doesn't get enforced at local competition but it's there and you can run into someone who will make a fuss. Hence you have a sleeveless trisuit for the short stuff and sleeved for longer course triathlon.
Sleeved trisuits are more aero and all that so I guess the ITU are trying to preserve the look of the sport with bare shoulders and all by enforcing sleeveless trisuits. There is no issue with swimming with higher end stuff because the fabrics are really stretchy around the shoulders.
I wouldn't use a sleeveless trisuit on the road, just use mine for the odd short distance tri. Sleeved trisuits are perfectly fine for road use, but due to minimal padding, you'll feel any issue with your saddle, fit, or too much cake over the winter months.
Last edited by Branko D; 03-01-21 at 11:56 AM.