I know I am repeating myself, but I want to make this clear. Diving within the limits of the tables is already extremely safe. The probability of getting DCS after diving within those limits rounds off to zero. Diving within those limits while on nitrox DOES make it safer, but because diving on air is already so very, very safe, the difference is not statistically significant.
You make an important point: Diving is reasonably safe if you follow the rules and use good judgment.
The incidence of DCS is about 2 out of 10,000 dives, or 0.02%. There are other things that scare me a lot more than that.
That said, we have to remember that group statistics do not necessarily apply to individuals within the group. And since a fair number of DCS cases have no identifiable explanation, a person can never be absolutely certain that HE won't be one of the two. We must ask, "Do I have some genetic or other unknown predisposition to DCS that I don't know about? Could I be one of those that gets hit for no good reason?"
Yes, the numbers are small. But if you could lower the risk from .02% to .01%, that would be a 50% reduction in risk!
Can Nitrox make that much difference? I don't know whether it does, but I don't know that it does not, either.
As I said earlier, I try to assess the risks, then take whatever steps I can to minimize them. Sometimes, for me, that means using Nitrox.
(Sorry for the long wind here at the end. Others got in some good finalizing posts while I was composing this one -- with numerous interruptions...)