At home births have caused deaths and brain damage that could easily be avoided in a hospital. The article hand waves these away by saying deaths caused by unnecessary surgery aren't scrutinized. To that, I say "then show it to us", because we can readily see the harm in at home births:
Author has recently submitted a patch to CPython which he believes will speed up the interpreter (looks too invasive and not discussed enough to have a chance of landing anytime soon IMHO): http://bugs.python.org/issue14757
There might be, but yeah, that's not the main reason for searching IMO.
See http://primes.utm.edu/notes/faq/why.html, but it boils down to "something really interesting can be found along the way, primes relate to other important topics so learning about them has intrinsic value, there's some money in it (but you have a 99.9% chance of spending more than the prizes in your search... and you still won't win)".