On average, what comes out of the grinder is electrically neutral, so there is no more point in grounding the grinder more than for any other electrical device.
The problem is at the particle (coffee grind) level, some are positively charged, others are negatively charged. The result is that if two particles of the same charge come close together, both will shoot out in opposite direction, and that direction is not necessarily where your basket is, and it will make a mess. If however, two particles of opposite charge come close together, they will stick together and neutralize, but by doing so, they will form a clump that may cause uneven extraction.
The idea with spraying the beans with water is to prevent static buildup before particles have a chance to form clumps or make a mess.
The problem is at the particle (coffee grind) level, some are positively charged, others are negatively charged. The result is that if two particles of the same charge come close together, both will shoot out in opposite direction, and that direction is not necessarily where your basket is, and it will make a mess. If however, two particles of opposite charge come close together, they will stick together and neutralize, but by doing so, they will form a clump that may cause uneven extraction.
The idea with spraying the beans with water is to prevent static buildup before particles have a chance to form clumps or make a mess.