The idea of the '3x4 kitchen rule' has some merit in terms of promoting balance and functionality, but I would not treat it as a hard rule. Kitchens should be designed based on how the client lives, cooks, and entertains rather than following a fixed formula.
If you're someone who eats eggs regularly and values speed and precision, then yes, an electric egg cooker can be a worthwhile investment. But if you're more of an occasional egg-eater, stovetop methods are perfectly adequate.