i don’t doubt it, but i think almost anyone trading for a living would agree that percentage-based methods of setting stop-losses are among the very worst, so to be fair it isn’t really saying very much! 
in all the independent, objective back-testing and forward-testing i’ve ever seen (and certainly in all the independent research work on this subject published by such authors as Tharp, Chande and Taleb, among others, in their various textbooks and academic papers), positioning stop-losses just beyond swings high/low of prices has significantly out-performed volatility-based methods
we all make our own decisions about this, of course, as about everything else, but that’s certainly good enough for me! 