For most resort riders on typical days, water-resistant boots handle the job just fine. They shed light snow and splashes without issue. But if you regularly ride in deep powder, wet coastal snow, or rainy conditions, a waterproof membrane like Gore-Tex is a game-changer. It creates a sealed barrier that keeps water out even when you're post-holing through soaked snow or sitting on a slushy chairlift.
Waterproof membrane boots are especially worth it for backcountry riders and anyone in wet climates like the Pacific Northwest. The trade-off is that they can run slightly warmer and cost more, since the membrane adds a layer inside the boot. If your feet tend to run hot, that reduced breathability is worth considering. But if you've ever ended a powder day with soggy, freezing feet, the investment pays for itself quickly.