Silicone dot grippers are small silicone dots printed on the inside of the shorts' leg hem that grip your skin to keep the shorts from riding up while you pedal. They're the most common leg gripper type you'll find across cycling shorts at every price point, and for good reason—they work well without adding bulk or feeling uncomfortable against your skin.
For most riders, silicone dot grippers are the best all-around choice. They hold your shorts securely in place during normal riding conditions and feel less restrictive than continuous silicone bands, which can feel tight on larger thighs.
The main thing to watch out for is that silicone dots can lose some grip when you're sweating heavily. If you typically ride in very hot, humid conditions or sweat a lot, you might find them slightly less secure than a full silicone band. But for the vast majority of riders and conditions, they strike the right balance of grip, comfort, and simplicity.