consider a fake tree; in many ways, it accurately replicates the experience of interacting with a real one. it looks similar, you can climb it, lean against it, sit beneath it. you can take pictures of it, throw things at it, punch it, admire it. but the similarities end there.
for a simulacra, a hologram, is but a very shallow simulation; a simulation nonetheless, but a static one, comprised of cached states, limited in the ways it can respond to observations. it cannot simulate an interaction with the base system which was not recorded into it prior.