Ear plugs/muffs do the same thing

I reject the premise of your argument.

Ever use a set of bone conduction headphones? These sit on the temple, in front of the ear, and conduct sound waves directly through the bone of the skull. Wearing earplugs does not reduce the effectiveness of such headphones. Bone conveys sound waves exceedingly well. You can damage your hearing with bone conduction headphones, even while wearing earplugs.

The reality is that earplugs or earmuffs are not adequate for fully mitigating the harmful impulse noise of common firearms. Injury is lessened by ear protection, sure, but it is not eliminated. No amount of ear protection can prevent a sound pressure wave from being conducted to the cochlea by the skull bone. Earplugs and earmuffs limit sound passing through the auditory canal; not the skull itself.

Silencers reduce the harmful sound pressure wave before it can be conducted by bone. As such, they are much more effective at mitigating harm.