Nobody cares how hard things are to code except for people are are already naturally disinclined to pay for software. Difficulty of execution may, for a very large swath of possible apps, be inversely correlated with success.
FWIW: The answer is "yes", followed (implicitly, because you didn't ask this) by "yes, people did pay", followed by (to the question you actually asked) "reread the article".
$25 is not that much; the secret is in making customers believe it's worth it, i.e. good marketing.
People pay a minimum of 1000 USD for an Apple laptop. I work on a 500 USD laptop from Asus, which I believe is just as good. But it's not as cool and people don't envy me :)
FWIW: The answer is "yes", followed (implicitly, because you didn't ask this) by "yes, people did pay", followed by (to the question you actually asked) "reread the article".