Do Stop Losses Really Work?

It would appear from Dr Vanstone's analysis, that trading the ASX top 200 using the 60 day EMA to plot buy/sell signals works best (historically) with no stop loss.

This makes perfect sense and would not see the need for a stop loss when a cross down of the 60 day EMA gives you the stop/sell point to exit. If one was wanting a tighter stop then surely a shorter EMA (say 30 day) for the exit signal would serve the same purpose.

I suspect the need for stop losses increases proportionately to the decreasing value of the market cap of a stock.