Pointillism (also called divisionism) is an artistic movement that involved placing tiny dots of unmixed colors side by side, with the hope that the colors would end up appearing more vivid than if they were used in the traditional method. Seurat was the main artist of Pointillism.
Additive and subtractive color mixture
The physical basis of pointillism is that it mixes colors from primaries by the additive rather than the subtractive method. This does, in fact, provide for a wider gamut (range) of color, but, as practiced by Seurat, a side-effect is that the dots are large enough to produce a texture that is visible even when the painting is viewed at an appropriate distance.
An ordinary computer screen works on the same additive principle: the picture is produced entirely of tiny dots of red, green, and blue, but unlike Pointillist paintings, they are so small as to be nearly invisible. In contrast, in an ordinary printed color picture the color is produced by spots of cyan, yellow and magenta ink which remove red, blue, and green respectively as the light passes through them. And indeed a computer screen can reproduce a wider and more vivid gamut than a printed page.