During your opponent’s turn, Set cards in your Spell & Trap Zones cannot be destroyed by effects. If a Set card(s) in your Spell & Trap Zone is destroyed by an opponent’s card effect: This card gains 800 ATK until the end of the turn.
Does not protect your backrow against non-destuction removal like Hey, Trunade!.
These types of Trap cards are activated when your opponent attacks your monster which makes them somewhat ineffective because your opponent can remove them preemptively. Bearblocker protects these battle Traps while they protect Bearblocker during battle.