It looks like the new Google's Pixel 4 watch comes with yet another incompatible change in charging technology. This is a ridiculous situation. The original Pixel Watch used one type of wireless charging. Then the Pixel Watch 2 & 3 removed wireless charging and swapped to a different charging mechanism. And now the 4 has changed again. So three different charging cables in under three years.…
If you mean a USB-C port in general, they can be made waterproof. If you mean something specific to putting one in the most compact form factor possible, that might be true.
They can be waterproof but are also non functional until the water is fully cleared from the port.