Few questions about speed days.

Question Number Zero: Does anyone here have "Speed days".... or "Dynamic blah blah...something" day ?

Question Number One: Doing regular deadlifts, or squats, or bench press at 50% of 1rm as fast as you can.. is that considered a speed day ?

Question Number Two: Do you have to be a professional powerlifter to get benefits from "speed days" ?

Q. 3: Can newbie/ or intermediate lifters benefit from speed days ?