Not to mention that a typical university will reward you with consequential marks in an exam if your general methods are correct but your final answer doesn't add up. Spend 15-20 minutes on a flight plan, stuff up a final calculation leaving your landing weight x kg out and you've lost all 5 marks and wasted a decent amount of time in what is already a very time critical exam.
Yes, the content covered in your average ATPL exam is fairly basic, but the conditions and nature associated with some of the exams can make them quite challenging, regardless of one's education or intelligence. This is especially true considering you might be undertaking these exams whilst trying to juggle a flying job/flight training. I completed a Bachelor of Aviation and I remember one period at the pointy end where within the space of a couple months, I was trying to complete my MECIR, had 3 full days a week at uni, whilst also completing multiple ATPL exams. My workload was considerably higher during this period than it was during year 12 when I was studying 2 advanced maths, chem, physics etc and it was considerably higher than any of my friends studying engineering who seemed to still have time to party on the weekends. I had an instructor tell me at the time that if you failed some of your ATPL exams, it would be a blackmark against you when going for an interview at airline down the line. You can imagine the feeling of dread when you take an exam, hit the submit button, wait anxiously for the result to load, only to see you've failed by 1%, you then have to immediately put it to the side because you've got to get strapped in for your final flight before your IR test at 0730 the next morning in a flight that will cost a couple thousand if you muck up.
Some people definitely may have an easier road than others, perhaps that's due to their superior aptitude, or maybe it's simply due to luck and/or not having to worry about finances. But I've got enormous respect for pilots in general because you have to invest a considerable amount of time and money for a career that is full of risk and completely up and down (no pun intended). Many people still look at pilots with rose coloured glasses and see it as a cushy overpaid job, you've also got the flight simmers who think it's all a piece of cake because they know how to configure an A330 autopilot and watch it autoland whilst sitting in their chair eating ice cream.
Anyway. There's some great advice on this thread. You'll be making an important decision and you really won't know whether or not it's the right one until the future arrives with the gift of hindsight. If all you want to do is fly, you don't want to wait and you're prepared to do the mopping up later if things don't quite work out as you hoped, go ahead and do an aviation degree. The courses are not all that well run from my experience and what I've heard from others, most of the universities just want to get you in, push you through and get you out in the shortest time possible so you can free up a space for the next kid. That being said, I don't think an aviation degree is useless outside of aviation, I've found it to be a talking point in many interviews and there are recruiters who realise there are transferrable skills that you will have, you've just got to make sure you've got other things going on in your life outside aviation.