You lead me to believe that they are targeting a niche "audiophile" market and probably not a commercial market. The concern in the commercial market would be energy savings vs. capital expenditure. Some commercial spaces actually introduce white noise into spaces to increase occupant density.
They target people that want quiet/silent cases, obviously not commerical, unless you're going after the long life/warranty service. Or you go for their industrial line.
They are targeting people who want nearly-silent fans for computing devices and will pay considerably higher than average prices for them. I have several of them, and they are vastly quieter than the competition. Wouldn't be worth it in a commercial space, but I want my house to be quiet.
In my experience fans from manufacturers like Arctic can be almost as quiet similar Noctua, but cost 50% less. The difference definitely isn't vast for most models, although admittedly there's more QC issues and variation than with Noctua.
A lot of Noctua sales come from their brand value. People put Noctua fans into their gaming PC's, use headphones while gaming on them, and then turn off the PC. You don't really need the most silent fan for that, but people buy them anyway for the looks & premium quality.
I do love Noctua's coolers though, I appreciate the well thought design, manuals and free upgrade kits when you upgrade your system to a new socket type. But for case fans I'll jut buy Arctic and save money, except for things like server systems that run 24/7 in my bedroom where noise and durability are top priority.
Audiophile products are a known scam.
This is an enthusiast product, as evidenced by the premise that you care about color-coordinating the inside of your computer.