Try a quick stop on studded tires on dry pavement, at 30-35mph. It’s like sliding on ice if you’re on concrete, plus the studs get ripped right out of tires if you’re on macadam.
Braking is only for emergencies. [if one is truly interested in fuel economy.]
My studded tires seem to have the studs wear well with the tread and I have never experienced what you describe.
Specific conditions vary.
Very true. Just like snow/ice. They probably cause as many or more accidents than they prevent. Also the tear the hell out of the roads and carve grooves in each lane, which increase hydroplaning and increased stopping distance when they fill with water.