That is true, charts are a reflection of historical data, but they can at times be useful in helping a trader to predict future pivot points.
Better stocks that have liquidity often times trade in channels and that can be huge for helping someone to decide what price to make their trades at.
When a stock starts moving within a channel they don't often stray further than a tick or two above or beneath the upper and lower trend lines. So you might not always hit your buy and sell point right on the nose but you can get pretty darn close. I've used this method with great success in helping me decide what price to place my buys and sells at.
Another useful feature of charts is that they can help you decide when to get in to a stock, or also when to sell your shares by looking at the overbought, and oversold indicators.
There are a lot of people that think sites like American Bulls will help them be a better trader. They get fooled in to following the success that American Bulls achieves when they show their initial 100 dollar investment and then proceed to show all the places where they bought and sold showing how much money they made. It's easy for American Bulls to always have winning results because they post their trades based on after the fact information.