The object is, not to stop.
A hard (seated, even) sideways skid will give you enough of a second to go around the back or side of whatever is in your path.

That's not saying to go out and bomb through every junction no matter what kind of traffic is crossing and think you can just skid around the cars! I stop at 80% of lights and bomb through the rest if it's clear.

Pedestrians don't count since they're so small of a target!

Eh, all that saying... it takes me quite a while to come to a complete stop. If I'm trying to, it just might be shorter than if you tried to use a rear brake alone to come to a stop.
But as said above, in a do-or-die situatuion, I can stop on a dime! Can't re-create that for all the dimes in the world though.