This brush is very versatile, you can control what they open depending on the pressure you exercise when painting and you can also use them sideways to get finer strokes or outline surfaces that are not too small.
They go well to make transparencies, to blur, to draw lines with the edge or to draw broad strokes if you use it on the flat side with all its bristles. You can make textures and if you age it a little more you can be surprised.
You can use it to apply the double load technique (two shades of paint on each end).
It is one of my favorites because of its versatility.