Albert Einstein liked to sleep 10 hours a night - unless he was working very hard on an idea; then it was 11. But he was probably sleeping faster than light.
Ha, ha, PHB looks like he would need some rest :) Anyway, my wife had a bit less sleep while she was breastfeeding our little daughters during the night but I think she was a bit more "exhausted" and "disordered" rather than "genial" :)
PHB has a problem differentiating cause and effect.
The cause is not the 4 hours sleep. The 4 hour sleep is the effect.
The reason of the 4 hours sleep is that the most famous geniuses had projects to work on, and got exited on them, either in a good way (an idea that they just couldn't stop doing) or in a bad way (a deadline to be met). Both make sleeping difficult for a person.