They are going inside the computer where they aren't visible. The point of a computer to me is to be powerful while being as discrete about it as it can be (i.e. quiet and no blinking rgb lights). I don't have a glass side panel, I run an older Fractal case with aluminum sides with sound dampening instead.
I never understood "form over function", but each to their own.
Speak for yourself :) My computer is pretty open, the fans are visible through the front and through the side panel.
I don't run RGB either though but I do like to style it.
And of course the "form over function" is part of that market niche that really pays a lot for something like a fan. Noctua aren't that special, as others have mentioned there are much cheaper brands with the same performance including sound level. You do pay a lot for just the branding.
I have some Noctua fans still going strong after a decade. Are there other brands that can also do that? Probably, I have some BeQuiet fans now too in a tower CPU cooler (couldn't get hold of a Noctua cooler during the pandemic), it will be interesting to see what happens in another 6 years or so with them.
And no, I don't change my computer every 3 years or so any more, so longevity does matter to me.