I don't know how many times I have been linked this video, but it is several, and I imagine almost all of them have never actually cycled in Finland during the winter. But I have, for many years, and I can tell you that it does in fact suck!
If the cycle paths are not plowed, you basically have no forward momentum, and even if you manage to cycle in it, your bike will refuse to go straight, especially when the snow is wet. And if they're plowed, they're still slippery to a point that wet asphalt could never be. Ever had to hard stop a bicycle on the snow because a car pulled in front of you? Not fun.
If the cycle paths are not plowed, you basically have no forward momentum, and even if you manage to cycle in it, your bike will refuse to go straight, especially when the snow is wet. And if they're plowed, they're still slippery to a point that wet asphalt could never be. Ever had to hard stop a bicycle on the snow because a car pulled in front of you? Not fun.