black and white
In the same way, a photo with a lot of colored elements in the background, even in the blur, will attract the eye and divert the attention of what is really important in the image. The black and white will help to purify the image, to make it easier to read. Some consider black and white not as a choice of photo processing among others, but as a creative technique in its own right, a directive technique in this case. This is to show without embellishment, not the reality, but the message of the photographer. Black and white is the return to fundamentals.