I guess you could call the striker "the hammer," in that they serve a
similar purpose. Still don't much like carry pistols or even defensive
pistols sans safeties or decockers. Even my Ruger 22, which fires rounds
via what might be called a massive moving striker, has a safety.
The assumption is if the striker/hammer is not left cocked after the
last shot, a safety is unnecessary and there is nothing for a de
cocker to decock
Your Ruger (Mk1?) leaves the striker cocked after a shot as did
virtually all SAs before the Glock.
A Glock pulls the striker back and slides a blocking bar out of the
way as you pull the trigger.
It's a Mark III. The problem with leaving the striker uncocked is that
all you have to do with that sort of pistol is pull the trigger to fire
it. Once you rack the slide on a Glock, the pistol will fire when you
pull the trigger and will fire repeatedly. Yes, that is how it is
supposed to work, but...I like the additional step of flicking the
safety off before firing a pistol.