There is a romanticized narrative of the founder that sleeps under their desk sacrificing every moment to make their dream come true; where their success comes from the extent of stress and hardship they were willing to absorb while their competitors didn't go to such lengths and are now left in the dust.

The rational mind knows that getting proper rest lets you work closer to your optimal and 5 hours of work at 100% is better than 20 hours at 20%. That's not as good of a story though and the optics themselves have marketing value so it may balance out in the end.