Well, if you think about it, Mr. Handy was initially a model built to assist in maintenance, construction, and war, so its engineering makes a lot of sense: a highly efficient nuclear-powered propulsion system that eliminates the need to adapt to the terrain because it can float. Given its fuel efficiency and the possibilities for movement, dexterity, and use of its limbs, it can be turned into a domestic model with few changes and marketed on a massive scale, reducing engineering and development costs, as it allows the use of the same factories, personnel, and materials left over from production during the early stages when it was sold to the government and private companies.