Boiling the camera still has huge optical advantages; every time a light path crosses a material interface you get more refraction and distortion, and when you're using a Pyrex container you have two more interfaces than you would otherwise (lens-air, air-glass, glass-water vs. lens-water). It's especially bad when the interfaces are curved, as they are in the case of most cookware.
So, this way you get way less distortion, and thus a much better view of the egg being poached.
(This is also why this view is so much more awesome than just looking from above, sorry undecided)