I never used traps in TW2. I try to avoid spending too much time navigating menus. Game mechanics such as alchemy, traps, crafting often all take copious amounts of time in bland menus, when I'd rather be spending more time out in the world exploring, talking to interesting characters, and getting caught up in twisted plots.
If there were a more streamlined approach to using traps (such as how potions automatically refill on rest in TW3) and they were readily available, easy to place in mere seconds, then, I'd be more interesting. One of the pitfalls of TW2 for me was how dependent the player had to be on Traps, Bombs, and Alchemy. Because if you only use a sword, then the first fight with fat balding drunk vagrant is more deadly than the Krayan. One of them armed only with a stick and a wooden barrel top as a makeshift shield could eat the legendary Geralt's lunch in two swings unless you perform 19 combat rolls and take pop shots between each of your 19 attacks.
That's not a fun combat system, and being forced to stun someone with Aard, bombs, or traps to one-shot them is the only alternative. I think TW3 has traps in the form of unique quest objectives for special monsters. That's good enough for me.