The cost of housing the criminal would be less, as there would be less of a need for restraining devices, barbed wire, etc. The idea of a prisoner not being able to socialize is also good, as they have more time to think about the actions that landed them in prison, and less time to socialize and develop more criminal ideas. The aspect of the Panopticon, and the other disciplinary techniques mentioned by Foucault, that would not work is the very thing that would make this idea so useful in prisons. The complete lack of socialization makes the Panopticon almost sick. To use it as a place of employment or education would harm society almost as much as it would help it.
Humans are social beings.
While more work would get done using such disciplinary techniques, humanity would be dehuminized. Yes, work would get done quickly and efficiently, but humans would become almost robotic. To think that the Panopticon would be useful in education children makes no sense. While it is true that the children would become educated more quickly, it is also true that they would not be complete people. Part of the education process is learning how to interact with others, learning control in a distracting environment, and learning about other aspects of socialization.