Is ATR a volatility indicator?

Could you elaborate on whether the Average True Range, commonly referred to as ATR, is indeed a volatility indicator in the world of cryptocurrency and financial markets? This metric seems to be mentioned frequently in discussions around market movements, but I'm interested in a concise yet thorough explanation of its role as a volatility indicator. Specifically, how does ATR capture and measure the extent of price fluctuations? Is it a reliable tool for predicting future volatility, or is it more suited for analyzing past trends? Clarifying these points would greatly assist in my understanding of this indicator.