It also gives you exposure to the school/campus that you might not otherwise get. We didn't think our DS would get accepted to NASS (since it is so competitive) and he was very keen to apply to USNA so we decided to sign him up for Navy Swim Camp so he could at least spend some time on the campus/talk with people etc. Murphy's Law -- the day we sent in the deposit for Swim Camp, he was accepted to NASS. Ended up attending both back-to-back and was very glad he did since it broadened his exposure to USNA. He was exhausted by the end of swim camp but he felt like it gave him a leg up on the people arriving the following week for NASS who had yet to experience/acclimate to the intensity. After both, he decided USNA was definitely for him, has applied, is 3Q'd and is anxiously awaiting a nomination.
P.S. and DS is not a recruited athlete -- just enjoys swimming; however, there were plenty of swimmers at Swim Camp who were definitely there for exposure to the coaches, etc.