When my son was young, and I thought about the future when he was a college player, I used to think "he's going to play in a college summer league EVERY summer." Now that he's done it for the first time, I have changed my thoughts on it.
First, if you are a stud P5 player and a legit major league prospect who has been invited to play in the Cape, YES, you should be playing summer ball.
Or, if you are a freshman who was redshirted or a sophomore who almost never played during the spring with your college team, you should consider playing in a summer league to get those ABs and IP that you missed all spring.
Or, if you are a HS grad who has been offered a chance to play in a college summer league then it might be a good opportunity to see how you fare against some older players.
But, if you were a kid who played or pitched A LOT in the spring for your college team and you are offered a spot in a run of the mill, average, and not prestigious summer college league, then maybe it doesn't make sense to do it and you're better off resting, training, working and enjoying your summer. And, it's not the end of the world to not play summer baseball.
Not saying FOR SURE DON'T DO IT. Just saying that it's MAYBE really not necessary if you got tons of playing time in the spring, maybe could use the rest and recovery, AND if the summer league wasn't a real high end opportunity.