I think this is real, in the sense that they got the results they are reporting and this is a meaningful advance. Too early to say if this will scale to real world problems but it seems super promising, and I would hope and expect that Waymo and competitors are seriously investigating this, or will be soon.
Having said that, it's totally unclear how you might apply this to LLMs, the AI du jour. One of the main innovations in liquid networks is that they are continuous rather than discrete, which is good for very high bandwidth exercises like vision. Our eyes are technically discrete in that retina cells fire discretely, but I think the best interpretation of them at scale is much more like a continuous system. Similar to hearing, the AI analog being speech recognition.
But language is not really like that. Words are mostly discrete -- mostly you want to process things at the token level (~= words) or sometimes wordpieces or even letters, but it's not that sensible to think of text as being continuous. So it's not obvious how to apply liquid NNs to text understanding/generation.
But it'll be a while, if ever, before continuous networks work for language.