Here is Heide’s third video. This one covers patterned blurs, which are fascinating.
How would you use them? Often they can be used in abstracts. But consider, also, that what are textures but abstracts? Usually low contrast abstracts with no huge color changes, but abstracts none the less. Just as an example of an abstract, I made a few brush strokes in Paint mode with some Water brushes.
Next I applied Blur 28, and fiddled with the Direction and Radius sliders.
Next I used Style>Painterly>Painter 2, Style>Tensor, Effects>Sharpen>2 and Effects>Raise>2.
Finally, I built a background using Blur again: Preset>Gradient, a couple of Textures, Blur, and Water-B (in the soon-to-be-released beta). I used Effects>Blend to bring in the brushstrokes, then Tone>Enhance 4.
Kinda nice for a couple of minutes’ work. Of course, you don’t have to limit yourself to abstracts. How about a surreal background blur?