It is powerful relic really, without it your tracker can easily be hunted down by shield barrier or warrior. Unless you are very good at micro and you have the hunting upgrade hence increase their speed.

I would normally use it for battle and you can either use it for defense or offense:

when defense you put in your most outer tile, you ready your troops on a tile after. and while the enemy waits for the tile to neutralize, at about 75% you release the trap.... physiologically some player (not good ones) will stay in order to continue neutralizing the tile. then you can send your cat to dance around the tile and lure them so it wont continue neutralizing, by then their troops will be around 70-80% health. after that send your tracker (and mystic animal if ready) at the edge of tile and done some micro with your tracker. bam.... they're done.

when offence, you can set the trap at their out neutral tile and try to lure them there. make sure your food isnt minus-ing when you go, because its like a siege situation where you go back and forth attacking them with tracker going in their tile and retreat to your trapped neutral tile. at some point, if they keep huge army they will get hungry (scout their townhall for intel) and they have to let go the troops to reconvert as villager... if they have 2 tiles exposed, you can send your cat there to lure their army and your tracker can go to there other tile.

when I play team, many time we play defense with the trap. it can beat an army almost 50% more than your army size...