The point about gas is certainly true, thought I can't speak to the rest as much.
While you're accelerating, you're giving the engine gas to keep it moving and prevent a stall. While braking you aren't accelerating, but you still need the engine to keep going at speed.
If you depress the clutch, it disconnects the engine from the wheels. The engine will then get a trickle of gas (even if you don't accelerate) to keep it moving while the car breaks.
If you don't depress the clutch, the engine stays in connection with the wheels. Their motion drives the engine - the reverse of normal - keeping it moving without burning any gasoline at all.
It's not generally a big difference, but if you're in the hills of Colorado you might care more.
While you're accelerating, you're giving the engine gas to keep it moving and prevent a stall. While braking you aren't accelerating, but you still need the engine to keep going at speed.
If you depress the clutch, it disconnects the engine from the wheels. The engine will then get a trickle of gas (even if you don't accelerate) to keep it moving while the car breaks.
If you don't depress the clutch, the engine stays in connection with the wheels. Their motion drives the engine - the reverse of normal - keeping it moving without burning any gasoline at all.
It's not generally a big difference, but if you're in the hills of Colorado you might care more.