No trader wants to get alerts all the time so a simple alert tool for indicators could be useful.
Lets say a trader doesn't want to get alerted every time an ma cross or macd cross or rsi ob/os happens. So it's not meaningfull to have an indicator alerting for everything.
Here is an example situation;
Basically trader enters an alert for when RSI (Candle 2) is lower than 70 and RSI (Candle 1) is higher than 70 or vice versa.
Candle 0: Current candle
Candle 1: Closed candle
Candle 2: Previous candle
Candle 3 etc.
This way traders can have alerts whenever they want one.