Gore-Tex is a thin membrane built into the glove that blocks water from getting in while letting sweat vapor escape. It's the most trusted and tested waterproof-breathable technology in ski handwear, and it genuinely works — your hands stay dry from both outside moisture and internal sweat.
It's worth the extra cost if you ski in variable conditions, deal with wet snow, or tend to run hot and sweaty. If your hands get damp and cold during a full day on the mountain, Gore-Tex can make a real comfort difference that cheaper membranes struggle to match.
However, if you only ski in dry, cold climates and don't struggle with sweaty hands, a proprietary membrane or no membrane at all may serve you just fine for less money. The key is matching the waterproofing level to the conditions you actually ride in — don't overpay for protection you won't use.