The rims offered by the dealership are specifically low resistance for EVs, they are called EV01 by FAST. The tires I believe are designed for EVs as well, they are Gislaved brand.
For background, the Fast EV01+ rims are around CAD $300 each. There are any number of good winter tires, and they range hugely in price, from about $150 to as much as $500 each. The Gislaveds are cheaper than most at under $200 each (depending on the model). So, as a package, balanced and mounted, you should expect to pay under $2,500, with tax.
Winter tires are generally not "low rolling resistance" tires (and should not be), so should your rims be super efficient aero rims?
Aero rims are really only valuable as an efficiency aid/range extender when you are travelling fast, at highway speeds, and the faster the the better. Are you doing long road trips in winter where traveling fast on well-maintained is possible? If so, then maybe winter tires are not such an important safety requirement. And if not, then the rims are really wasted.
So my view is that, for most people, standard rims, likely a bit cheaper, and the best snow tires you can find/afford, are the way to go.
Will some of the additional costs be offset by better mileage and/or increased life of the tires?
Winter tires are generally faster-wearing than summers, but some are better, and the choice of tire is independent of the rim choice. More expensive aero rims, used only in winter, will lively never offer a payback in terms of electricity savings. You might save 2-3 kWhs of energy per week if you drive far and fast on aero wheels, and how long will the energy savings of maybe $1 a month take to pay for those wheels.