Jeez. If only we'd had a thread about over-priced exotic cables before, then things would have been much easier.
Anyway. Are they worth it? No idea. Not in my opinion, but then 'worth' is meaningless in the context of the seriously high-end market. Will they make a difference? Compared with what? Simple fact is that it's impossible for any cable to add anything electrically, so the best a cable can do is to take less away. From my experience, I suggest you can reach the dizzy heights of performance at which no difference is audible by spending under £100. Possibly substantially less. Do I know any of this for certain? Well, I can take a very good stab at it, but if you're asking me whether I've 'heard' a £30,000 mains cable, then no. I haven't. I could possibly wrangle a review item, but it's unlikely. It's mostly unlikely, because I couldn't write a review in sincerity anyway.
And the big question: do I care? Not in the slightest. My 'give a s**t' factor is as close to zero as it's possible to get. The positive I can see is that if anyone buys some, the dealer is likely to make a few quid and that may help them stay in business. As it's Analogue Seduction and from one or two dealings in the past, they seem to be among the good people, that's a plus point. Also, it means they may have a bit more in the pot to do a decent part-ex deal on something one of us buys, so that's a win-win.
I'm seriously not in the least 'troubled' by all the uber-high-end stuff. I'm not ever going to buy any of it, so why would I care? It's easy to get wound up by the inequity of a society where such potential purchases exist, but that's the world we live in. Screaming about the goods for sale at that end of the market is never going to change it. As for the sort of person who can afford to drop £30k on a mains wire, we're talking about people to whom £30k is pocket money, so they won't care either.