After almost 9 winters of every day commuting, my experience in this part of the world where snow and ice is not too unusual is that I use studded tyres on the commute about 15 days of the year.
They simply provide the extra grip needed on slippery thin compacted snow, ice under snow and, of course, black ice. You still need to be careful with your bike handling and treat the road with respect as you would with any damp, cold winter ride. You do need your slippery road techniques - leading with the rear brake, gentle cornering and hawkeyed anticipation of problems up ahead, especially on the downhills.
The studded tyres come out with fresh snow that sticks to the roads, with forecast temperatures less than about -2C and when I know there is likely to be ice.
Thicker snow needs very big tyres and big nobbles, neither of which I have...
The main downside is the 1-2kph penalty due to the extra rolling resistance and weight.
The upside is that stability on slippery surfaces and the extra workout trying to maintain speeds...