The 30-day is useful in and Forex trading for placing stop orders for entry.
In the example above, a trader may want to initiate a Short position on a break below the support trendline.
A good place to enter this trade would be a price break below the support trendline minus 50 to 100% of the current ATR value.
ATR Bands provides a useful visual overlay of the current ATR value above and below the current price to speed up order entry decisions.
In true TradingView spirit, the author of this script has published it open-source, so traders can understand and verify it. Cheers to the author! You may use it for free, but reuse of this code in a publication is governed by House Rules. You can favorite it to use it on a chart.