Use spells and traps to keep your monsters alive and continue controlling the field. Use Enemy Controller and Windstorm of Etaqua to change enemy's battle positions when they attack. Using Mirror Wall will defend your monsters while also destroying the attacking monster.
Decreasing your life points by 1500 will allow you to activate the Sleight of Hand. Use Autonomous Action Unit to decrease your life points by 1500 while also special summoning a monster from your opponent's grave, or you could also use the effect of Amazoness Chain Master to decrease your life points while also taking a card from your opponent's hand.
The Clowns don't have a specific skill of their own.
They basically use "other skills" which might be helpful to them.
-Endless Trap Hell
Sleight of Hand is another useful skill which can help them buff Sgt. Electro.
Thus, Some Clown Control players use it.
It doesn't make the deck a Sleight of Hand Control deck.
It is just a Clown Control Deck fishing for a useful skill.
As far as the Sleight of Hand deck goes, The truth Sleight of Hand deck was very good!
It did reach King of Games.
However, It was before the World Championship + before 3 Star Demotion came out.
3 Star Demotion made huge impact on the deck.
The Sleight of Hand deck use to run fewer Barrel Dragons because it was hard to bring out a 7 star machine for 2 tributes.
Players ended up getting rid of "Sleight of hand" & replaced it with 3SD.
Than they increased Barrel Dragon to max since it easier to summon him with 3SD.
However, you can still see some of the left over Sleight of Hand machine decks in certain Machine 3SD deck builds.
Look for the 3SD machine deck examples which have the level 4 machines still in them.
Sgt. Electro, Twin-Barrel Dragon, & King