Not necessarily, but it depends on where and when you ride. Pants without gaiters have a standard hem at the bottom with no built-in seal around your boot, meaning snow can easily sneak inside when you're in deep powder or sitting in snow.
These pants work fine for spring skiing, warm-weather days, or casual resort laps on groomed runs. They're also common in fashion-focused designs that prioritize looks over technical features. Some riders even prefer them for touring because they're lighter and more breathable at the cuff.
However, if you ride in powder or wet snow regularly, skipping gaiters is risky. Cold, wet feet can ruin your day fast. If you already own pants without gaiters but want to ride deep snow, you can buy separate standalone gaiters to wear underneath — just know it's an extra piece of gear to manage.