I don't much care for all the "oh but the energy usage" claims in most tech things: it's all electricity, and it's all fungible. It usually seems to roll out as a proxy for "I don't like this thing".
Like even with cryptocurrency, there were a lot of people mistaking the issue of scalability - namely that "as a store of value" crypto would consume incredible amounts of other resources (and a lot of people got stuck trying to figure out how somehow "a hash" could be reclaimed for useful resources) to do less then alternatives, with "the energy usage itself is the problem".
Finding optimizations for LLMs is good because it means we can build cheaper LLMs, which means we can build larger LLMs then we otherwise could for some given constraint, which means we can miniaturize (or in this case specialize) more capable hardware. The thing which really matter is, can the energy usage be meaningfully limited to a sensible scaling factor given the capability that makes them useful?
Because environmentally, I can install solar panels to do zero-carbon training (and if LLMs are as valuable as they're currently being priced, this is a no-brainer - if people aren't lying about solar being "cheaper then fossil fuels").