I think all criminals everywhere should have to work off the expense of their incarceration. If pedaling to generate power is useful to the community, then they should be alloted a power/day routine. Besides, exhausted criminals are much less likely to get into further mischief in prison. Plus who knows, it may turn out to be a great training plan for future Tour de France contestants.
All power to the cleaver people of Brazil, make them pay for their crimes to society!
If there was a method to improve on efficiency, it would be great to use at home, but let be realistic. For home use I see no major impact to our large energy footprint. A typical household may use 50 to 100 KWhr per day, so I do not see the human gerbil experiment replacing the city power grid ;-)
Lighting is a practical use, given the improvements of LED efficiency, however they may other practical uses for remote and rural areas.