Gore-Tex Infinium is not fully waterproof — it's designed to be windproof and water-resistant instead. While it'll shed light snow and brief exposure, it won't keep your hands dry in sustained wet conditions like a storm day or sloppy spring snow. The trade-off is breathability: Infinium lets moisture vapor escape far better than standard Gore-Tex, so your hands stay drier from the inside out.
Infinium shines for high-output riding where you're working hard and generating heat, like skinning up in the backcountry or aggressive resort laps on cold, dry days. If you run hot or hate that clammy, sweaty feeling inside your gloves, Infinium keeps things comfortable. It's also great for dry, bitterly cold conditions where breathability matters more than waterproofing.
Skip Infinium if you regularly ski in wet climates, deal with rain or heavy Sierra cement, or tend to run cold and need maximum weather protection. For those situations, standard Gore-Tex is still the safer bet.