oh yeah, studs are are not a lot of fun to ride on, but chicago seems to be at that perfect latitude where we get an absolute crapload of freeze thaw every winter. we'll have some snow pack on the ground. then during the day it might warm up into the mid-30s, creating a little snow melt that forms small puddles in the streets, then at night it will dip back down into the 20s and all those little puddles will freeze over just in time for my morning commute. then it will warm up up just a touch during the day to melt a little more snow, then refreeze over night, and again, and again, and again. it can go on for days at a time.

i didn't know about studded tires for my first winter of bike commuting and i took several spills on ice. none were terribly serious, but i wised up to the importance of studded tires after that first season.

luckily, i have a dedicated winter bike in my stable that lives with studs on year round, so i don't have to play the tire swapping game. on winter days when i have a high degree of confidence that the streets will be clear and dry and/or temps will be above freezing, i just ride my regular commuter because studs are, as your said, boat anchors.