An intercepting safety is another line of defence agains accidental discharge.
I think it matters little whether this is an intercepting safety sear, like those used in Boss and Purdey sidelocks or an intercepting safety bolt, like in some Scott guns.
The point is - what is there to stop the tumbler hitting the striker in the event that the sear/bent connection should fail or be jolted out whithout the trigger being pulled.
If you don't have an intercepting safety, the gun WILL fire if the sear is jolted out of the bent, with an intercepting safety, it will be prevented from so doing.
Well made locks accidentally discharge rarely to the point of never, but that extra insurance has to be credited as a better system in my opinion.
