Ohhhh…you’re inviting a lesson on vector mechanics…Since volts x amps = watts, what is the practical difference between watts and VARs?
The only time I've encountered VAs is with battery backup supplies, which stubbornly insist on being rated in VAs while all electronic equipment only lists how much electricity it uses in the more reasonable Watt number.
From the viewpoint of the power generation plant, really, nothing. They have to generate it. Unity power factor loads typically have only VA (power). Motor loads, things other than resistive loads, have VA + VAR. The VAR is the current/“power”, sometimes called reactive power, required to create the magnetic field—it does no ”useful work” but still must be generated by the generating plant and transmitted/handled by the power companies.