Faster output of design resources
The grid allows teams to move quickly and efficiently. Providing fewer decision to make, the grid reduces time spent fiddling with the elements in design. It also makes things from a development standpoint, as it’s easier to anticipate values instead of having to discuss or measure for each element or margin.
High fidelity mockups
Elements sized according to the grid will guarantee the highest fidelity rendering of graphics and type, given that they will have pixel perfect dimensions.
Aligning Nets Design with industry standards
In Google Material design, created with mobile, tablet, and desktop in mind, all components rigorously align to an 8dp square baseline grid and all typography aligns to a 4dp baseline grid.
While Apple is not rigorous about aligning to an atomic grid, but most elements are sized to fit on a 4px grid. Importantly, outer margins in native apps are always a multiple of 4px.