The standard side-release buckle is the most common chin strap buckle you'll find on cycling helmets, and for good reason—it's reliable, proven, and easy to operate with one hand. You simply push the sides to release and click them together to secure it. For most road, gravel, commuter, and recreational riders, this buckle type works perfectly well.
The main downside is that it can be tricky to operate with thick gloves, especially in cold weather. It's also worth noting that not all side-release buckles are equal in quality—cheaper ones can become stiff or break over time, so check that the buckle feels solid and operates smoothly before buying.
Unless you're a triathlete who needs lightning-fast transitions, or you're buying a full-face mountain bike helmet (which uses a more secure D-ring system), the standard side-release buckle is all you need. It's inexpensive to replace if it ever breaks, and its simplicity is a strength, not a drawback.