I never heard of them.
If not for HN, I would never know they existed.
I don't think the remark about "nerd prestige" holds, but beyond that your points boil down to marketing.
And how an unknown company changed its hiring practices is hardly front page news.
Like I said, they are relatively small but they are definitely not “unknown”. Out of curiosity, could you name any quantitative trading firm, or trading firms in general? You specifically may happen to just not be paying much attention to this sector.