Most of the devices in buildings, telecom, and more, require DC power. For example, LED lighting, 5G DAS equipment, variable speed HVAC systems and pumps (VFD motors), laptops, and EVs, all need DC power. Actually, any device with a battery or that uses semiconductors needs DC power. This means that we're living in a DC world with an AC infrastructure, which makes the operation of these DC devices inefficient. Providing DC power to these devices directly, reduces energy wasted by inefficient AC to DC conversions.
It's also worthwhile to note that DC power suffers from less line losses/voltage drop along cables than AC power, which makes distributing it along longer lengths of cable more efficient than distributing AC power. You can read about that in our blog article about line losses.
Read more on our blog: 5 Reasons DC Electricity Should Replace AC Electricity in Buildings