Of course, like open source software, free fonts do their best to undercut the market for individual professionals to make a living, but creating fonts isn't free.
I mean, what are you comparing against? Rendering text in the null font? Sure, if that's really all you have then I guess spend $250 on an actual font, but even VGA is perfectly serviceable for a lot of tasks, and I'm not sure this font is $250 better than VGA, let alone something like DejaVu or what have you.
>creating fonts isn't free
At this point we should ask if it was necessary to create another font in the first place.
No, I'm comparing against "whatever the default is". It's the same with chairs or beds. You can get "something to sit on" or "something to lay on" for $0 or close to it. But I will gladly pay a premium for the same reason - I spend 8+ hours a day in a chair, and 8+ hours a day in bed, so I don't even blink at paying any price to improve my daily QOL for years to come. Even if it's only by a little bit, a little bit of QOL over thousands of hours is an investment in your own happiness.
> At this point we should ask if it was necessary to create another font in the first place.
There's plenty of room for more fonts to exist. I have yet to find a monospaced coding font I like with Japanese support, and would gladly pay $250 if I found one.