It's an efficiency thing.

Not if the engine is warm.

Uses more fuel!

Anytime you’re not being smooth with the vehicle you’re adding additional wear on everything in that system. Hard acceleration puts extra force on the clutch/torque converter, put extra pressure on the gears of the transmission, puts extra strain on the driveshaft puts extra strain on the U-joints of the driveshaft, or the CV-joints of a drive axle, and extra strain on the contact patch of the tires, even if you’re not accelerating hard enough to spin the tires you may still be going hard enough to peel a micro layer of rubber off.

Similar with hard braking, more wear on the brake pads, excess heat in the pads and discs, plus extra wear of that outer layer of the tire tread.

Hard cornering can put additional strain and friction on suspension components, and steering components, ball joints, bushings etc, plus there’s that added strain on the tires to get you around that hard corner. In a NASCAR race the cars are going near 200mph around the track, they generally aren’t skidding tires or spinning tires, but with just the force of the hard cornering they peel off these little hard rubber bits from the tires so much so that partway through the race there is a clean and dirty part of the track that does or doesn’t have these little rubber marbles rolling around.

Remember, the more g-force you feel in any direction the more wear you’re putting on a specific part of your car. Smooth is key