but there's literally NO scenario in which I could recommend AMD 590/5500XT (at £150-£200) over 1660 Super at £200. NONE.
So in a specific use scenario where the RX590 out performed or performed neck and neck with the 1660S, you would still recommend the user spend an extra £50? Granted the price of the RX590 has since bumped up to £165 from £150 but the point stands. You're basically arguing that a user that only plays one or two games where performance is within 1-2% between the cards should spend more money for no reason.
As for that version of the card being trash, countless people have bought it and have zero problem with temps or noise. The original revision of that cooler was used on the RX580 and was admittedly poor, they released an updated and improved V2 of the Red Dragon 580 which I believe shares the same cooler as the currently available Red Dragon RX590.
The features you're touting aren't relevant to everyone, I couldn't personally care less about VRS for example.
Regardless, assuming costs at £150-160 even for general use there are scenarios where the RX590 is a better purchase, budget considerations being one of them.