Braking in a stick shift car... truth or myth?

Yes true. Slowing using the brake is the usual way to slow a car down with a manual (or an automatic). The only problem is when you wish to accelerate and at what rate you wish to accelerate at from the speed you have slowed to. A lower gear is required and that is the reason to change down. Changing down to slow the vehicle may wear the clutch out - well it did for me.