Q: “Why is it not possible to use a USB-C power supply directly?”
A: The honest answer is, that it was planned to be used with a USB-C power supply directly, but it simply does not work. Most USB-C power supplies “communicate” with the plugged in device and then turn their power on. This is not possible with the WordClock. So this is why a USB-A power supply with a USB-A-to-USB-C cable is required. You will find 2 very good ones in the parts list.
A: There is an advantage to this anyway. Because such USB-A-to-USB-C cables seem to have a better standard, they work much better than the previously used Micro-USB cables.
Vielleicht ist das im Kommentar von @petl@feddit.org die Ursache: https://feddit.org/comment/2637724
Ich hab mal gelesen, dass auch bei DIY-Projekten ein Problem ist, so z.B. bei diesem hier https://www.printables.com/model/749967-wordclock-16x8-2024?lang=de