Well from my viewpoint which is most likely the norm for most people, I'd need 6 fans costing me £140 vs £30 while being able to spend it else where, I get that they do the job better but the end result for me isn't worth it.
It'd be different if my budget mind was more willing, but £25 a fan is too much, even me getting 2 just for my 240 AIO I don't see value as that would cost the same as the whole unit did when i brought it, while I'm on a Ryzen 1700 the cheap fans it came with still allow me 4Ghz without issue or temp issues.
Then there is the ice gaint that is going to cool far better at far less cost so idk but really just my take on it, like all things in life you live by your means there really is no right or wrong on anything people buy.