Emergency brake is a term used by those that do not understand the function of the parking brake.
Remember all the Mopars with the T handle under the dash to apply the parking brake? Not much braking force using your off hand there. Which is why you set the parking brake by first applying the service brakes fully, on Mopars with the parking bake in the rear drums, not at the trans. Not a very effective "emergency brake" when it locks the handle/pedal in place with each application. As mentioned, it'll likely worsen the situation in most cases when you panic, jam the brake on and lock up the rears.
A random look at an FSM, 70 Dodge in this case, calls it a parking brake and goes into how it function as one.
With both the handle and foot operated parking brake you can control the amount of braking by keeping the handle turned or the release handle pulled so they don't lock. I have driven using the old emergency brakes with very little issue. Just didn't go fast or a long way. I'd be willing to bet I'm not the only one.
