The indicator is trend-following, and based on averages, so by its nature it doesn't pick a market bottom, but rather shows when a rally has become established.
It is not regarded as well-suited to commodity markets, since bottoms there are more rounded than the spike lows found in stocks.
A slightly different version of the indicator is still used by the Investors Chronicle, a British investment magazine.
The main difference is that the Investors Chronicle version does include the sell signals, although it stresses that they are to be treated with caution.
This indicator greatly helps with the definition of the intermediate term market moves of 6-weeks to 12-month duration.