I don't think that this is just a nit, it implies a real mismatch between how these models work, and how modern computing hardware works. People have built ternary computers in the past, but to the best of my knowledge nobody's made a serious attempt at it in half a century.
You can always use two bits to store a ternary value, of course. But then it wouldn't be a 1-bit LLM, now, would it? And that doubling in compute resources required would make a tangible difference in how one has to think about potential efficiency improvements. Also, ternary tritwise logic implemented on binary hardware is unlikely to be anywhere near as efficient as binary bitwise logic on hardware that was specifically engineered for the purpose. This leaves me thinking that the research teams involved continuing to refer to these as 1-bit LLMs must be interpreted as knowingly engaging in dishonest marketing tactics.