Is leg training actually useful for tricking?

Basically what the title says. Someone said to me that training my legs (weighted exercises, pistol squats, etc.) will lead to big improvements. Is this true?

Personally I have my doubts about it, as I don't see how slow exercises that require strength should improve explosive power. Also, when I look at really good trickers, they don't have "buff" legs either. I am interested in your opinion on this.