Factory wheels come out quick, but they often skip small details. With hand-building, you can catch every issue and make it just right. It's a craft that's disappearing, and that's a real loss.
Mechanical discs were so much simpler to maintain back then.
They don't make a noticeable difference for most people on the road. You're better off spending that cash on a proper fit or better tires.
Seriously, just grease the threads and most creaks vanish, save your cash for beer lol.