Hasta La Motion!

I wonder what would be the best way to motion blur an animated GridWarp distortion?

CornerPin is motion-blured by default. Why GridWarp isn’t?

I noticed in render panel of GridWarp some controls for ‘shutter’ and ‘shutter offset’, so there must be a reason for these controls to be there even if they’re not affecting the look.

Optical flow would be an overkill because motion data is already in animated grid points so why not use that data instead of analysing the footage?

I tried to add a motion channel (100% white) before the GridWarp but then the image is evenly blurred even without any animation.

Excuse my ignorance and thanks for your help.