My Radiant Acoustics Clarity 6.2 sound superbly with no sub. But I assure you they really are even better with a stereo pair of Lyngdorf BW-2 subwoofers.
Admittedly, one big advantage of having great subwoofer integration as provided by WiiM is the fact that you can get along with pretty small main speakers. That's the obvious use case and it's important for many users. But there is still this other thing, that the perfect position for (sub-)woofer is not necessarily the perfect position for a speaker playing upper bass, mids and highs. Being able to separate the position can be beneficial even with pretty bass capable main speakers, even if it's not a must.
I'm happy WiiM gives us these options to choose from.
You might suspect fashion here, but I assure you it's not. Many ways to skin the cat and I sure as hell enjoy listening to my friends pair of Quad ESL fed by a 303 power amp and 44 pre-amp. No sub, not room correction, pure fascination. But in most domestic environments room correction and sub(s) provide great bang for the buck.
Unfortunately, both still need some work and understanding to be set up correctly in many cases.