The lack of clarity is in keeping with the USB C connector itself, which may supply or accept power at various rates or not at all, may be fast or slow, may provide or accept video or not, and may even provide an interpretation of PCI Express but probably doesn't.
It gets even worse.
I now have two cheap Chinese gadgets (a checki printer and a tire inflater) that have USB-C ports for charging, but will only charge with the wire that came with the gadget. The other end of which is an old-style USB plug.
It seems that USB-C sockets are cheap enough parts to use them for everything, even if the manufacturer isn't going to put any actual USB circuitry behind them.
Edit: Three. I forgot about my wife's illuminated makeup mirror.
I repaired device like that a while back - it only took two half-cent resistors and a half-assed soldering job to make it compatible with standard USB-C cables and chargers: https://www.nfriedly.com/techblog/2021-10-10-v90-usb-c/
Note: If it just needs 5V power (Like many microcontroller-focused devices), USB C is convenient, because chargers and cables are ubiquitous. And they all (WIth exceptions like the one you mentioned) support 5V DC power.
Bonus: YOu can enable USB 2.0 data transfer as well for firmware updates, computer interfaces etc.
So: Cheap/ubiquitous part, everyone has cables + AC adapters to their local plug: I think it's a great default power connector.
Ah that's a fun misuse of USB ports. The companies will often even dodge issues with the USB-IF by labeling the ports as Type C and letting the customer's mind fill in the word USB.
I wish these devices would just use barrel jacks, labeled with the voltage and polarity. But these manufacturers know that the USB-C port weighs into buying decisions (and they know that most people have zero clue about the difference between a physical port and the electrical/protocol specs).
I keep a few of these around to deal with this: https://www.adafruit.com/product/6323
Very annoying though! The devices are just missing a couple resistors which is probably less than a cent on the BOM.