Studs add time. My commute is 7.5 miles one-way. Takes 24 minutes if I'm flying on my road bike. Add 3-5 minutes if I take my rain/snow bike. Add another 3-5 minutes with that bike with studs.

Another example: On a descent on my way to work I can hit 35 MPH on my road bike, 28-29 on my rain/snow bike, and, I don't quite remember, but I don't think I break 24 MPH with studs. (buzzzzzzz)

It's winter. It's icy and snowy. Slow is good. Plus, after pushing around a studded bike all winter, in the spring, when you switch back to road tires, you will be a MONSTER.