My son's experience with camps has run the gamut. He got a phone call (illegal?) in the fall of his junior year from a Big 12 saying they had seen him play at a showcase and wanted him to come to their camp. Many hundreds of dollars later (the school was out-of-state), our son never heard another word from that school despite emailing them fairly frequently after that.
This summer, son got a personalized email inviting him to camp from a Big 12 recruiting coordinator who had never seen him play but seemed to like some of the stats and other information son had emailed him. We were skeptical, but bit the bullet and paid the fees. Son did very well at the camp, but the coaches did not express any evident interest in him and we thought the camp was a bust. Imagine our surprise when a JUCO with ties to this Big 12 contacted our son out of the blue. They had received a recommendation from the Big 12 who saw him.
My son just committed to a school whose camp he attended last December. The school had seen him play just 2 innings prior to that (summer after sophomore year) and we could definitely tell that son's performance during the camp had interested the coaches. They came to see son play 8 times this past summer and made an offer, which was a dream come true.
So..... some camps are a waste of time while others can be very beneficial. Obviously, you have to play well to attract attention.
Best wishes to your son!