My interpretation: Small buck converters are cheap and efficient, and so many parts need different voltages anyway (1.8V, 1.5V, 1.2V, etc.), that what you want

My interpretation: Small buck converters are cheap and efficient, and so many parts need different voltages anyway (1.8V, 1.5V, 1.2V, etc.), that what you want to do is distribute the 12V from the main PSU and then locally convert it to the voltage you need. If you are already putting buck converters everywhere, it makes sense to raise the voltage coming from the PSU, because you can reduce the current supplied by the PSU. Only the power supply will be running at 12V, almost everything else will be running at a lower voltage. (Would you rather supply 120W at 12V/10A or 5V/24A?)