Fyi I also was very bemused by this, I own Radiance & Bathys and percieve a pretty dramatic gap in sound quality (in Radiance's favour). I spoke to another chap on Reddit who has both too and he said the same and was glad it wasn't just him. I was lucky to get the Radiance for £320, I can see why maybe someone comparing a £1200 Radiance to a £700 Bathys might lean more toward Bathys, but I do think the sound quality difference at least reflects the price difference at full RRP. In pretty much every way you can imagine, Radiance is better.
Bathys is still one of the best wireless headphones i've heard. But as far as I can tell that is a completely different category of headphone in performance vs wired, passive headphones that are full size. Maybe I misinterpreted DMS here and he was commenting on the overall package, as in an Airpods Pro 2 over wired iem kind of deal, given ease of use. But I find it hard to believe anyone as serious as he is about audio would think the Bathys sound better than Radiance.