If the double action is used every time with the revolver, then the trigger will be uniform and the same pull length and weight with every shot. This allows the shooter to grow accustomed to the trigger quicker because it's going to behave the same way every time it is pulled.

What is the point of a double action pistol?

Double Action Handgun

The trigger both cocks the hammer (or striker) of the firearm which prepares for the actual firing to take place and then fires the handgun. For each single trigger pull, the gun is performing two actions, and that's why it's called “double” action.

Is a double action pistol safe?

Most double-action revolvers have no external safety devices; a sufficiently firm trigger pull will always result in firing. ... Most modern double-action revolvers have an internal safety, either a hammer block or a transfer bar, that positively prevents firing without the trigger being pulled.