For one, it can be great fun. Athletes who love their sport love competing in it without the least intention of wanting to go pro. For many of them, sports is as much a part of their identity as being good in, say, math or singing. It’s what many of them DO (and would probably find a way to do it competitively even on an intramural level if college teams weren’t available.) And you do it while meeting fascinating people and making contacts/friendships that can last a lifetime. You get to travel. On someone else’s dime.
Two, it can be a huge resume booster. Many employers respect the kind of commitment and discipline (and competitive spirit) it takes to be a college athlete – they see these as good qualities in prospective employees.
Three, it can actually give you skills employers want. My daughter was a team captain of her Div 3 team which entailed a lot of organizing and even van-driving. Because of this experience, being accountable for people, schedules and equipment, she was offered a highly selective position of a team leader on several summer Outward Bound expeditions.
Today, her job has nothing to do with Outward Bound or her sport: it has everything to do with her education. But she’ll be the first to recommend college sports as a part of students’ education, if at all possible.