Embodiment of Apophis is a Reptile trap monster with 1600 attack, but it's also good for defense since it has 1800 def. Swamp Mirrorer is the more offensive trap monster since it has 1800 attack, and it can become any monster type that you want when it's summoned. Making it reptile gets you piercing effect if you have Lion Alligator on the field.
I chose this over the gems. You get gems any time, but we can only get this card from the Pick-a-Gift Campaign!.
I'm not sure who wrote this, but Snake Whistle does not work for monsters destroyed by battle because it cannot activate during the damage step. Please do some research on card rulings before spreading misinformation.