If someone has found a way to use a particular indicator or strategy EVEN IF YOU CAN'T USE IT, more power to that person. The bottom line is profit / results, and there are many ways to achieve profit / results. I had a similar "conversation" with people about software recently. Again, WHATEVER WORKS for a particular person is what matters. Peace!
I think where indicators help is in aiding traders visualize whats going on in the market. The ADX for instance will give you confidence that a market is trending or not. But at the end of the day Price action is king.
Its inventor gave up on it and went into another line of business. He peddles now "delta"- stuff, some kind of esoteric mumbo-jumbo.
I like using ADX for swingtrades, but not daytrading (I primarily use time & sales, volume, sector percent change, 2d hi/low breakouts for daytrades) ... Here's the method I've developed, fwiw: http://www.esignalcentral.com/learning/likepro/strategy/volume/default.asp Primarily I use ADX to help give decision support beyond a SMA support for increasing volatility at time of entry, in addition to volume. It's not a holy grail, but is one of a handful of indicators that's useful, to give support to "whether or not the stock's volatility" is heating up. Then of course I like to add volume etc to avoid getting in on exhausted patterns etc. ken