Calgary winter commuter (10 years), e-bike owner (1 year) and Bosch e-bike certified tech here! Yes, you can use your e-bike in winter, but you will need to take a little extra care with the battery. As others have said above - bring the battery indoors when you aren't riding, definitely make sure it is warm before you plug it in to charge, and consider some insulation around the battery when you are out and about. (I used a woolly sock on mine. It was fine!)

Physics can't be changed, and that's what dictates the slightly lowered range and efficiency of battery systems in cold weather. I have a short commute, only 5km each way, and I didn't notice any change in my range even at -20C. I stopped riding once it got colder than -25C, because I can't really breathe comfortably at that point, but according to Bosch there is no real lower limit for their systems.

I put a studded tire - Schalbe Marathon Winter - on my e-bike's front wheel, but found I didn't need it on the rear, because the long wheelbase and low center of mass make the bike a lot more stable than any of my other bikes have been. I'm also using a route with very good snow clearing, thank you, city of Calgary! I only fell once last year, which is an improvement over previous years.

One thing caught me by surprise, and that was the necessity to re-calibrate my personal layering system, which I'd refined over a decade. Suddenly I'm not working as hard on the bike, so I wasn't warming myself up as much! My -10C clothing and gloves had to be bumped up to -5C. Totally worth it.