Hold on, so now you want to use USB C for data transfer? Which means you want to what? add more storage to the watch? That sure seems like a solution looking for a problem you're only floating as a result of choosing USB as the charge port, which we probably shouldn't do.

And that's not just much less battery than on the Pixel at 420mAh, it's even smaller than the CMF Watch 2, which reports 305mAh and is only seventy bucks (and if anything seems smaller than all of your examples). So yes, there is an impact on battery. And no, that's not acceptable. Because again, ALL smartwatches need more battery than they currently have.

The point of the always on HR monitoring and screen isn't that they exist, it's that they are a massive battery drain. A smartwatch where you turn those off will last several times more than the same watch with them on, particularly on entry-level devices like ones you point at. And you would ideally wnat those on in a perfect smartwatch while still getting multi-day battery life. Right now we just don't have that because you can't work your way around physics.

Now, for an experiment? Sure, go nuts. Put a solar panel in there. A hand crank. Who cares, weird hardware is weird and weird is fun.

But to solve the problem with the ever-changing charger standards from the mainstream manufacturers weird won't cut it. You need a solution that fits all cases with near-optimal performance. USB is just not it for this form factor, and if anything focusing on it distracts from the very real need to come to a proper standard in this space, which I find somewhat annoying.