Looks like a single gang switch box mounted on top of 3 6-gang boxes. The electrician may not have had the option to use 8 gang boxes, which iirc wont fit inbetween studs on 16" centers. and the boxes, mudrings, and cover plates cost a lot more. and he'd still have 3 rows.
Better question is why someone needs 19 switches in one location... seems like massive overkill to me... certainly some of those lights could have been combined.
As ugly as it looks from the front, if it is what I think it is, I bet it's 10x uglier from the back/inside, especially if it's wired with MC.
eta: I've seen nearly as ugly in a hotel ballroom, it had like 12 single gang boxes for fluorescent, can, sconce, and chandelier lighting in one area like that. Someone built a locking plywood cover/cabinet over it all so it was hidden from general view.