Why Right Edge ??

This should be simple and obvious to "traders". Almost all "traders" use some form of price charts to trade the FX market. The prices are all on the left side, which means prices already dealt with or is currently where the market is at. Can't really go back wards to trade yesterday's prices can we? So the "bucks" come from whats going to happen next on the " right edge" What happens on the right side of the chart is what's important. But come to think about it....if one could buy the low yesterday and the sell the high yesterday..that would be an amazing "edge" ......hmm..... -)) Well, what ifs don't pay the bills, but what is may.