Price Labels are balloons that display price or index values above and below significant peaks and troughs. The main purpose of Price Labels is to visualize significant highs and lows of price action. When you enable Price Labels on your chart (check the Price Labels box under Chart Attributes to enable), you can quickly see the highest and lowest values displayed. You don't have to look up these values in a separate table or use the Inspect (crosshair) tool.
Price Labels may look like they gave good signals in the past, but they’re not designed to be trading signals. To generate price labels, we look into the future when deciding where to display them. You’ll never see a price label appear at the far right edge of the chart. This is why Price Labels can't be used for trading signals.