Velcro side tabs are the most common waist adjustment you'll find on snow pants, and for most resort riders, they work great. They let you quickly tighten or loosen the waist on the fly—super handy when you're adding or shedding mid-layers throughout the day.
The main trade-off is durability. Over time, Velcro can collect lint and lose its grip, especially if you're cranking them down hard or washing the pants frequently. If you ride dozens of days per season, you might notice the tabs get less secure after a couple of years.
That said, Velcro tabs offer a solid adjustment range and are easy to use even with gloves on. For the average rider hitting the resort 10–20 days a year, they're usually plenty. If you ride hard every weekend and want something that'll last many seasons without wearing out, buckle side tabs are the more durable upgrade.