The Curve crossing over the zero line is a great long signal. Although using this on the doesn't provide the best signals, it's useful when paired with the weekly charts (I'll attach that below). In short, a long position crossover on the should match the trend on the weekly charts.
In this case, the long signal on the daily Curve is matching the up-trend on the weekly. To make the signal stronger, the weekly is about to crossover the zero line as well.
Also need to include that Both the weekly and the daily have a nice uptrend, and that prices held up on the last significant .