In most cases I would agree with you. It is much easier to see and hear, if something goes wrong with an air cooled system over a water cooled one. And usually, with the size of modern coolers, they can dissipate heat, quite effectively, even without a fan attached. Air passing through the PC case from case fans is often enough to keep CPU temperatures within safe working limits, if you are not over-clocking.
However, having said that, I watercool my own PC. I did a lot of research before going down this route and I have not had any major headaches. I built my own loop, rather than using an all-in-one solution and that is probably why I haven't had any real problems.
The one time my pump failed, my CPU temperatures didn't climb to high, because I over spec'd my loop to allow for this eventuality.
Each method of cooling has its advantages and disadvantages. As they say: "You pays your money, you takes your choice."
