Snow pants without waist adjustment rely entirely on proper sizing to stay put, so you'll need to be confident in your fit before buying. You won't be able to fine-tune the waist as you add or shed mid-layers throughout the season, which can leave pants feeling loose or tight depending on what's underneath.
The bigger issue is keeping snow out. Adjustable tabs help cinch the gap between your jacket and pants, creating a seal that blocks powder on deep days. Without that feature, you'll likely need a separate belt, which can be uncomfortable under layers and still won't seal as effectively against snow.
Pants with no adjustment are typically found on budget or fashion-focused models. They can work fine if you're a consistent size and mostly stick to groomers in mild conditions—just know you're trading some versatility and weather protection for a simpler design.