You'll find that light, quiet and flat trajectory are all relative when it comes to crossbow. They are nowhere as light as vertical bows, much louder (although some CBs are not a loud as other) and their trajectory is related to their arrow speed and weight. Other than the stock to steady the shot and being easier to learn how to shoot accurately, they offer no advantage over vertical bows. In addition to the negative factors you mentioned, generally speaking, you will get only one shot. Most cannot be cocked in a tree stand without MAJOR effort and movement, not to mention noise. They require patience to use effectively. But, hey, that's why I prefer single shot rifles and handgun too.
If you're an accomplished bowhunter, they may not add much to your game. Only way you'll find out if it's for you is by shooting as many different ones as you can.