Having been fortunate enough to speak to a few people directly involved in both buy and sell side trading for institutions, the market makers ... those who drive the market said that Fibs, nor any kind of TA was used at all. No sell side person I spoke to even used a chart to a significant degree...only the price. Given that his job was to offset risk, he only needed the prices relevant to his order books.
Considering Retail Fx only constitutes approximately 6% of all daily trading volumes...I fail to see how this puny amount can make any drawn level on a chart significant as a predictive tool.
Nothing said here changes that view, because there is nothing quantifiable.
Sure, i get people can use them as a reference point...but that's all it is...it has no greater or less significance than a macd, ma or anything else people spend so much time on.
Wealth comes from what you keep, not what you earn