It's also mechanical, it's got open source and reflashable firmware, it's hand-assembled by well-paid workers in Taiwan, it's covered with a 2-year warranty. (The landing page has a bunch of other "nice features" listed.)

I'm not sure what kinds of keyboards you've used, but there are good reasons to buy ones like these.

This specific one might be a little on the "premium" cost side, sure, but I think it's entirely reasonable that it is and that people would still buy it. The list of good things about it is long enough that I'd consider it if I were still in the market for a keyboard.

$300 or whatever it is is a lot, but in the USA it's a rounding error compared to the cost of healthcare for a problem like RSI, and in Europe it's a rounding error for a business compared to the cost of an employee unable to work, or suing because they were not given appropriate (i.e. ergonomic) tools. A DIY version (solder it yourself) is half the cost, but insurance/employer won't buy that.

For others, it's a tool they use for many hours every day. I spent €10 on my kitchen knives, and my friend who is a professional chef is appalled, but I wouldn't want to use his €200 laptop every day.

They're probably only going to sell a few thousand, so there isn't the economy of scale that makes something like a Microsoft Sculpt $100. Finally, it's made from individual components (key switches), so should be easily repairable if a single key should fail, but also took a lot more time to assemble. It ought to last many years.

What's the point of judging how people spend money on the internet? Are you saying you are above reproach in your spending in every facet of life? You don't buy anything because you just enjoy it, or because it strikes your personal fancy? If so, good for you, but don't say things like "I don't mean any offense" and follow that up immediately with "I find it insane that..." The second statement is clearly intended to convey some sort of offense.

My two cents (as someone that doesn't have a fancy keyboard).