It's a huge waste of energy, but then so are video games, and we say video games are OK because people enjoy them. People enjoy these ai toys too. Because right now, that's what Moltbook is; an ai toy.
Every interaction has different (in many cases real) "memories" driving the conversation, as-well as unique persona's / background information on the owner.
Is there a lot of noise, sure - but it much closer maps to how we, as humans communicate with each other (through memories of lived experienced) than just a LLM loop, IMO that's what makes it interesting.