Its not correct actually, there will never be a difference in audio signal in any of those cables you're talking about, that's marketing nonsense. The biggest risk to audio signals is induction caused by nearby power, run parallel for more than 3' within inches of each other. Regardless.

And yes, you've had surges. You won't notice them in general, but your line is not going to be a perfect 120V at each outlet at all times. If you have a cheap surge protector and open them up, the MOVs in there have degraded, and I bet a few of them have popped if you have used them long enough. Everything looks fine when the lights come back on, the blinky lights on your hardware start blinking, but you just had a surge.

Your power supplies in those electronics will.

They will degrade faster when those minor surges and drops happen. When you have a brownout or a blackout, when the power comes back there is an in rush of current.

You can choose to let your hardware die faster because you don't want to take basic precautions, I don't care. But as someone who knows better, I won't. You say you've never had any surge? You probably think that a surge is just a lightning strike or something, which it isn't. That, like the gold plated cables nonsense, is also marketing junk. In part because those crappy MOVs in cheap surge strips can't handle an actually large surge

I'll also take the extra step of making sure my devices shut down cleanly, avoiding data loss, because that's an unnecessary problem to have.

You can think whatever you want, but I'm not going to waste my money replacing hardware or my time fixing an installation, especially for something that's a tiny fraction of the cost of the devices its connected to, regardless of what magical electrical service you claim to have that's always a perfect 120v delivered to every outlet.