Honestly, the illusion worked very well for me. The picture appeared in full colour until the instant I took my eyes off the dot, then it showed as black and white.
What's with the eye-rolling and humbugging, you two...?
If you're saying the picture just changes from colour to B&W in the video, I think you're wrong.
Try it twice: first time, look away from the dot as soon as the 'colour' appears. Instant B&W.
Try it a second time and keep looking at the dot until the vid ends. No B&W, although the colour might fade a little as the afterimage of the negative colours fades from your retina.
If you're saying it is a real illusion, just not a very impressive one.... there's no accounting for taste.