having some confidence in your tent lets you relax (somewhat), read a book, catch up on sleep drink hot chocolate, periodically step outside to clear some snow from around the tent and empty the pee bottle (do not forget the pee bottle). if you are unable to sleep because your bracing your tent for the next gust, or buried in spindrift that blows thru the mesh inner, you will probably survive (dead people usually aren't found in tents unless they are in an avalanche), but it will take a lot of the fun out of the adventure, but may provide good cocktail party chit-chat at some future date. Also, if you question your shelter you might decide it's better to hike out than hunker-down, and that's when they will find you in the spring thaw.
in reality, many people use a 3-season tent in winter conditions and not have any issues. you just need to decide where you want to be on the risk curve.
enjoy your trip.