What you fail to understand is that " accurate" in an acoustic perceived experience way cannot always be reduced to "accurate" in an electrical way by a limited set of electrical parameters among all possible ...
Human ears are trained by evolution to identify some qualities relating to timbre experience be it speech recognition or natural sounds, or musical one etc , This timbre experience acoustic qualities may be related in some case to the various parameters and material composition belonging or beside or near the vibrating resonant source and affecting it ...
Very simple experiment :
Put a big chunk of shungite on an amplifier...
Or try a big chunk of quartz...
Then try it many times and you will feel the difference with a music piece ...
Even if your electrical measures tool set will not detect any change in the amplifier specs you will hear a more compressed sound or a more meaty one with the shungite chunk and a more "clear" or less compressed or more high frequencies oriented sound with the quartz ...This is caused by the very different composition of these minerals affecting the playback system in such a way as impeding or improving the soundfield and timbre experience for the EARS/brain not for your measuring electrical tools... 😊
The fact that shungite work always in his way and the quartz work in his own opposite way is an OBJECTIVE fact...
If these AC cables did make the usable signal more accurate don’t you think they would use them?