[kbolino]

I have a laptop with USB-C ports which cannot charge from them at all. Instead, it has a DC barrel connector, and that is the only accepted charging source.

That same laptop, and a desktop PC I have, do not support USB-PD over USB-C, so only 5V/500mA trickle charging is supported. This isn't the charging direction I was thinking of originally, but since this seems to be the direction you're thinking of, it's worth mentioning.

Also, neither of these ports are Thunderbolt. I'm pretty sure they are USB 3.0 at least, which doesn't have terrible speed to be fair, but still is somewhat limiting at least as far as the laptop is concerned since it means there's no way to get PCIe speeds.

Granted, this is ~2019 era hardware, but nevertheless the USB-C ports are not nearly as useful as they could be.

[johnisgood]

I read it as "USC-B ports can't be used for charging" (this is exactly what was said), but if I plug my phone into these ports, my phone will charge, and there can be data transfer as well.

[kbolino]

Yes, and that's not what I meant. I'm sorry for the confusion, but I have clarified already. I meant charging the host from the peripheral, which could be a wall charger, a battery pack, a monitor, etc. I was thinking of laptops when I wrote the original comment.

I also elaborated that, even when we consider the other direction, i.e. host-to-peripheral charging, many USB-C ports on PCs only provide baseline USB power levels (aka "slow charging"). The implication (that I now make explicit) is that such poor charging performance would not justify removing all other ports from the computer. I didn't mention this originally, because I didn't think of it then, but now that you have brought it up, I would add it to my argument.

The crux of that argument was: USB-C as the only port type is acceptable as long as those USB-C ports are full featured. That means (again, to be explicit) that they support Thunderbolt, DisplayPort, and bidirectional USB-PD (aka "fast charging"), though obviously one of those directions is not applicable to hosts that have no battery (e.g. desktops).

In other words, if the USB-C ports are no better than USB-A ports, then they are not good enough to take the place of other, dedicated port types.