In my practice with Caitlyn since her release, it's good to set traps in the river bush to potentially stop a jungler from ganking your lane. It's common practice for many jungle champions to sit in either the triangular bush (or tribush) or the bush closest to the lane, and they can get caught in the trap, immobilizing them and revealing their position. A more aggressive tactic is to trap the bushes against the edge of the lane, where supports like to hide and poke at you from afar. Since you can have up to three traps at any time that last for 4 minutes, it creates a blocked path they must either get caught in themselves or avoid. You can use it to escape, too, if you drop it under you while being chased.
Honestly, they're her best utility, arguably over her net. Kill set ups, escapes, and vision of position on the map for your team.