Going against the old adage of "Don't dig for gold; sell tools to miners"?
Yeah but the gold have been dug for awhile now, plus there are competitors with just as easy access to the market and his is only a little different from the competition.
But there's a big, big pile of gold (normal iOS or even Mac users).
Developer tools can't be an easy market to succeed in. You aren't going to get many impulse buys.
That works great, unless said miners have an almost ridiculous quantity of tools just lying on the ground waiting for someone to clean them up a bit and start using them.
The point in the article is that it is ahead of other apps in Dev Tools from established companies who should be selling more than 10 copies a day.