On the question of whether an expensive cable is any good at all:
https://www.youtube.com/watch

SPOILER:
No.

I can confirm and disagree with you that buying expensive cables is worthwhile (under certain circumstances). It depends very much on the output, receiving and intermediate devices used. And especially on the cable length and resolution. With full hd resolution, hdmi matrix switch and samsung tv. I already have problems with 10m to the switch, even with better cables. And 10m from the switch to the beamer ditto. Ps3 to tv already with 2*1.5m from/to switch or to beamer anyway, depending on the cable.
The ps3 has a poor output signal and the samsung tv a poor receiver. I found out that different devices with the same cables can make a big difference!

But HDMI is digital, so it either works or it doesn't. Picture and audio quality will be the same. But it may not work at all with a cheap cable, but it does with an expensive one... For example, I have a cheap 7.5m cable here. Full HD or less is not possible without a switch. That's why I switched the tv box to 720p, and now it works.

Sincerely

If you want 4k and 10bit for HDR (UHD Platinum), you need such a high-quality cable - unfortunately, cheap 18Gbps cables are not enough, especially with a cable length of 10m!