For an LLM, you have clear stages of mostly feedforward computation over finite numbers and a perfect way to reconstruct the computation.
For meat, even if you model it under a purely Newtonian approximation, you need to simulate at least the immediate closed system around it which is continuous, thermodynamic, chemical and so on. You'd need to choose an arbitrary time step and update enormous amounts of coupled physical state to get an inexact simulation of a minimal slice of reality.
You would have a much harder time obtaining even a substrate-independent dead organism, comapred to LLMs that are already substrate-independent, which is basically what my notebook example shows.
Yeah the last line is a cheap shot, possibly at myself.