Overclocking is just a way of getting more out of your system for free so i'm all happy with it. But i don't take it to the extreme like watercooling. I think by then you're be paying more to overclock it than you would getting a faster chip anyway. I got a nice air cooled system running at about 30% faster than stock and i only payed $10 for some fans (which allowed me to get it another 10% higher). So it's worth it to a point then it's just for enthusasts.
ehhh, kind of....yeah water cooling can be rather expensive and all, but I wouldn't really call it 'extreme' or anything. My GPU is always at 38C idle and around 44C load, which you just can't get on air...you might be able to get the temps down or close to that if you're in a cold room but the differences between idle and load won't be so small.
As for CPU..well....in my case I got a crappy venice so it didn't matter whether it was air or water cooled either way.
However the deafening sound by my previous setup that had air is nice to have gone since I've got a much quieter water cooled system.
I didn't necessarily get water cooling because I thought it'd overclock much further...although that is the case in some instances, especially with a GPU, but I also wanted it because it basically ensures you, your CPU/GPU will never overheat...it's basically impossible with the exception of your pump dying or something like that.
Besides if I paid for a faster chip then I wouldn't have any money for cooling
You do however make good points