On the following websites: https://www.the215guys.com/, https://saffronindianbistro.com/ there is a repeated pattern of black dots over the large jumbotron images.
What is the reason for the overlay of dots?
They are simply putting a low opacity black overlay over the images so that any light colored elements they put on top of the images (carousel arrows, white text, etc.) will stand out and not get lost in the noise.
The reason for choosing dots over a solid overlay was likely entirely a design choice because they thought it looked good.
Source : Link , Question Author : Community , Answer Author : DasBeasto