A person can disagree all they want, but it really depends on the firearm in question. On my Beretta the safety de-cocks the hammer and when I use that feature it not only drops the hammer, but prevents the pistol from being fired at all, unless I put the de-cocker back in the "fire" position.
Rotate the lever down, hammer drops and pistol is incapable of firing. Pulling the trigger does nothing, and the firing pin disconnect is engaged. Rotate lever back up and I'm back in DA/SA business.
I much prefer this system to one I have to manually de-cock. Less user error potential.
Remove finger from trigger, rotate lever, done. I never have to touch the trigger, or hammer, and don't need to do any finger gymnastics in the process.