Not sure about that -- if you look closely at the pics of the Huawei watch you'll see that the body extends out towards the lugs quite a bit. I suspect the extra tech is hidden in those chunky bits. The G watch R has the same styling; and whilst that could just indicate that Huawei and LG have no design smarts (which is often true) I'd be a little surprised that the two companies independently hit on the exact same ugliness by chance.
I suspect that at the moment some compromise has to be made: you can have a flat tyre, you can have a giant bezel, you can have chunky bits-that-aren't-lugs. One thing I'd be pretty certain about, though, is that Motorola didn't go with the flat tyre look just for kicks.
Here's an old article about Moto's design choices if you're interested.