Heat is heat, be it from an oven, hot water, or a hair drier. Heat is what sets the egg (makes it turn hard). The reason that water is usually used is that water transfers the heat to the egg much more quickly than does air. The egg simply cooks faster in water. That being said, the water has to be brought up to a hot enough temperature to cook the egg (above 170' F.).
The reason for better textured eggs (as reported in the comments section of the link), is that the eggs weren't overcooked. A good many home cooks over-cook their boiled eggs. My wife used to insist that eggs had to be boiled for ten minutes, at a rapid boil. This makes the eggs more rubbery, and affects the flavor of both the egg white and egg yolk. I bring my water up to a light simmer, where the bubbles just start coming to the top, and then back off the flame just to keep the water hot. My eggs aren't jostled by the boiling water and so I don't get cracked shells (great for Easter eggs), and I cook for about 6 minutes. The egg white is more tender, and the yolk is set, but more creamy (less dry).
For a large number of eggs, the oven will work great. As I stated, heat is heat, no matter where it comes from. But in an oven, for the air to transfer enough energy to cook the egg, it must be at a hotter temperature, than in water due to the heat transfer efficiency of the two mediums. And even then, they will take longer to cook in the oven. But like the p posted, even with the increased cooking time, the eggs can be cooked in one batch, rather than several batches in a pot of water, which will make the total cooking time shorter in the oven.
Seeeeeeya; Goodweed of the North
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