Your Solterra will most likely use its connection to your home WiFi for OTA updates (our 2021 Outback does). Also, when you connect your phone to your car's WiFi hotspot, it will in some locations give you internet service where you might not otherwise have it - IF your car uses a different cellular carrier than your cellphone. At least that's true in the US, I'm not sure how the various cellular companies' coverage maps differ/overlap in Canada.
This has been especially useful for us in the Outback. The car uses AT&T, our cellphones were on Verizon which has some notable network holes in places we travel to, so it was useful to have a backup data/voice connection at those times. We recently switched to Google Fi, which in the US uses T-Mobile and US Cellular, and even though its coverage seems to be better than Verizon's in some areas, it is importantly different from AT&T's - so we'll still benefit from having overlapping cellular coverage. So long as we keep paying the $25/month for the car's cellphone service.