Improved power factor effect on national grid
Large industrial plants are penalized for having too poor a power factor, when the power factor is poor, it creates more stress on the power plants generators (uneven acceleration),  which reduces the lifetime of some of its parts, so usually there is a monetary motivation for an industrial plant to atleast attempt to improve its power factor, 

In comparison due to all the switch mode power supplies in use today, with many of the cheap import products not using power factor correction, residential and office tend to appear capacitive, which means industrial plants get some range where by having a large inductive load can make things more consistent

As for what would change, less heat in the overhead wires, slightly less voltage drop over unit distance, and lower loading on the transformer stations meaning higher lifetimes, a lower risk of brownouts, Having a better power factor also usually comes with less harmonics on the mains, which would otherwise be waste heat in the EMI filters of most power gear,