When I started training in Catch Wrestling, we were told about the difference between a hook and a submission. A submission hold is one where you apply a joint lock to a person, apply pressure accordingly until they submit or the limb is broken. A "hook" is a move where the person has no time to tap.....it's snap, no tap mentality.
While all submission holds can be turned into hooks, not all hooks can be turned into submission holds. There are some moves in Silat which cannot be used in submission aspects simply because they are very easy to escape and there is no control. If you try to control the move and submit someone in a controlled manner...it will fail every single time. However, if the person uses that same move with the mentality of a quick break.....the move can be applied no problem and be very effective. Many people see styles like Silat and think it's silly to think those moves would work to submit a person but they are misunderstanding the move itself.....it's about breaking the limb in a fast, snapping and explosive movement.
Here are some examples of submission holds:
Double Wristlock/Kimura(depends on your terminology)
Notice on all of these moves, even though the guy is working hard to get the break......he is still keeping them in a controlled manner. Nothing has any "juice" on it and if the limb breaks, it's merely incidental because the person did not tap quick enough. The key here is that there is time for a tap out.
Here are some examples of what would be called a "hook" :
Heel Hook(completely rips the ligaments in the knee)
Standing Armbar Snap (fast forward to 2 minutes into the video) :
As you notice, the difference here is that there is no time for a tap. Even if the guys in the video wanted to tap out, it would be a waste of time.
Personally, I find this no suitable for MMA as it's a sport with rules so the person should be given the opportunity to submit rather than having their limb broken. However on the street, breaks are the rule as far as I'm concerned.
There are several advantages to the break rather than the submission on the street. One big one is the "friend factor" when street altercations occur. If the person has buddies around and you start scrapping, you will get jumped. The second issue is the "weapon factor" meaning that once you start tusselling with them, I weapon may come into play. If you are rolling around on the ground with someone and playing the submission game, there is a possibilty you could get stabbed numerous times before you realize it.
A little known issue with breaks too is how they can be applied on the feet in a striking situation. This is one of the things that I personally love about the Filipino and Indonesian styles of fighting namely Silat. Moves that would never work to submit a person would work perfectly with a "breaking" mentality as defense to strikes.
This is also a difference between the sport of "MMA" and realistic street fighting. While MMA techniques can be applied on the street just as effectively, there are some things due to the rule set that MMA does not prepare a person for on the street. This is why I always made it a point to have "MMA classes" and "street classes" for my students.