If you pushed the brake and clutch in, the brake would remain engaged until you let up on the clutch. If forget the mechanism used, but it effectively kept up brake pressure until you started to let out the clutch.
Not sure why it went away, perhaps modern clutches are better than their old counterparts, or the handbrake made it redundent.
The problem with this is that “essentially no rollback” is still worse than “no rollback”, and that you have to quickly lunge at the gas pedal, which makes this method damn near useless if you just want to move forward a tiny bit (e.g. when you’re parallel parking).
Some people seem to have the attitude that using the handbrake is the “wimpy” way to do it. The way I see it, the times when you absolutely must use the handbrake to start on a hill are the times when you want to be well-practiced at it.
Why would you have a four wheel skid? Are there cars that the parking brake control activates the brakes on all four wheels? In any vehicle that I’ve looked at, it only operates the brakes on the rear wheels. That’s a useful thing to keep in mind.
I think one of the reasons why us U.S. citizens might not use a parking brake on a hill is that in many American vehicles (especially older ones) this brake is operated with your left foot. The left foot is also your clutch foot. You then have to bend down to reach the release lever with your left hand. That simply wouldn’t work when you are trying to take off on a hill. Notice also that I’ve been using the term “parking brake”, since not all of these are operated by hand. My current car does have a hand operated parking brake, but my truck (late 90’s model) is still foot operated.
Personally, I use a three pedal approach if the hill is steep. My left foot is just used for the clutch. I keep the toe portion of my right foot on the brake and use the heel of that foot to press slightly on the throttle. As I release the clutch, I let off the brake while applying more pressure to the gas pedal. No hand brake is necessary and there is no extra wear and tear on the clutch. My work car is approaching 200K miles (not kilometers) and is still on the original clutch, so it must work ok. 
As to Subarus. I don’t know when they were supposed to have stopped adding the no-rollback feature, but it must have been recently as my girlfriend’s 2003 Subaru Forester has it. It always surprises me as I rarely drive her car.
As to why we call it a parking or emergency break, the majority of American cars are automatics, and many of these have a pedal on the far left of the floor for the parking break, thus it is not a hand break. I think the terminaology must have caught on from that.
On preview:
RogueRacer, a manual with a foot activated parking break? What kind of car is it?
You have me thinking here. One old truck for certain. A 1971 Olds Cutlass that I had in high school (I still have it in fact). A 1978 Cutlass with a 5 speed that I had back in my military/college days. I did mention the older vehicle thing in my first post. I don’t deny that all of the newer 4 cylinder cars that I’ve owned have hand brakes. Those hand brakes are fun for doing slides on snow or for parking on hills, but I’ve never needed it for taking off on hills.
I should also mention that I do have to use the three pedal thing (that I described in the first post) in my race car. It doesn’t have a parking brake.
I know you aren’t asking me, but since I wasn’t specific before: my 1997 Mazda B2300 pickup has just this setup.
ALL Mercedes cars have foot operated parking brakes.
Just goes to show how often I ride around in Mercedes.