The Bowler's attack has a knock-back effect similar to Fireball and can push all units except the heavy ones. And just like fireball, his knock-back does not reset the charge of a Prince, Dark Prince or Battle Ram.
The Bowler has a linear attack that passes through all troops. Because of this, he can damage support troops behind a tank. To maximise the damage output of this attack mechanic, you must always take placement into consideration. Since his attack passes through troops he is an excellent crowd control card, capable of taking on most ground swarms. Also, If placed directly behind an Arena Tower, the Bowler can counter a Goblin Barrel and stay alive for a counter-push. However, this requires good timing. His knock-back is also a great disruptor, separating support troops from the tank or delaying units such as Hog Rider from reaching the Crown Tower.
The Bowler is one of the best counters against spawners. He can one-shot Spear Goblins, Fire Spirits and Skeletons. He can also take on Barbarians since he constantly delays them with his knock-back, giving himself enough time to take them out. If he lands the final blow on a Tombstone, he will destroy the Skeletons that would have spawned from it as well. He is also a very strong counter against the Witch since he can easily tank her attacks and will kill any skeletons she spawns.
When defending against a Bowler, cards such as Minions and Inferno Dragon are very effective since the Bowler cannot retaliate. Despite his splash damage, his slow attack-rate means that he can still be taken out by swarms if he is surrounded.
He has a slow hit speed and low damage per second, so the player may need to back it up with troops with fast attack speeds and hard hitters such as the Musketeer and the Witch.
He can counter Elite Barbarians due to his knock-back ability and high hitpoints.
He is not very good at countering tanks, due to their high health and their inability to be pushed back.
On 24/8/16, a Balance Update decreased the Bowler's Elixir cost to 5 (from 6), decreased its hitpoints by 7%, and its damage by 10%.
On 19/9/16, the September 2016 Update changed his description. The description used to say "This big blue dude digs the simple things in life - Dark Elixir drinks and throwing rocks. His massive boulders bounce off their target, landing behind for a double strike."
He is the first troop that can push back other troops with its attack, and also the first one with a linear rolling attack that can go right through units.
The description was taken from Clash of Clans, though there actually isn't Dark Elixir in the game. Also, before the September Update, the description used to be wrong, as the boulder rolls, not bounces.
Although the Clash Royale Bowler is similar to his Clash of Clans counterpart, in Clash Royale his rocks actually roll while in Clash of Clans they bounce, hitting 2 areas instead of 1.