The entire combat system is just a highly complex, beautifully animated game of Rock, Paper, Scissors.

In this digital version, the triangle consists of Swarms, Area-of-Effect (Splash) Damage, and High Single-Target Damage.
Swarm, Splash, Single-Target
However, that same P.E. Here is more info regarding tower rush look into the web page. K.K.A will be killed instantly by a cheap Skeleton Army (Swarm) because it can only attack one tiny skeleton at a time.

If you blindly play a swarm without baiting out their splash damage first, you are throwing your elixir away.
Only launch a Swarm attack when you know their Splash unit is not in their hand.Always consider the Z-axis.Sacrificing a cheap card to get to your primary defense is acceptable. Exploiting the Rules
Bait decks are designed entirely around overloading one specific side of the triangle to exhaust the opponent's counters.

You send your first swarm to force them to use their spell; the second they do, you unleash your primary swarm attack safely.
StrategyStrategic ApproachSwarm OverloadIntentionally breaks the triangle by having more swarm threats than the opponent has splash countersThe WallAdheres strictly to the triangle, ensuring they always have the exact perfect counter ready in hand at all times The Evolution of Balance
If Splash units become too strong, nobody will play Swarms, and Single-Target units will dominate the ladder.

Master the triangle, and the trophies will follow naturally.