The premium anti-fog coating makes a real difference if you're pushing hard on the mountain. It adds a hydrophilic (water-absorbing) layer to the inner lens that actively pulls moisture away, keeping your vision clear even when you're working up a sweat skinning up a backcountry ridge or skiing hard on warm, wet storm days.
For casual resort laps in normal conditions, the standard dual-lens setup handles fogging just fine for most people. You'll notice the premium coating earning its keep during high-exertion touring, humid conditions, or those tricky in-between temperatures where fogging is most stubborn.
One important catch: that premium coating is delicate. Never touch or wipe the inside of your lens, or you'll strip the coating and defeat the whole purpose. Always let your goggles air dry after use—storing them damp degrades the coating faster.