I think it depends on how it’s done. The human could think so, but the fluffy, lacking the ability to exceed its programming, fully believes that it’s sapient and hence capable of genuine emotional responses.
The Worst Birthday Ever by Skrelptastic approaches this topic this from the perspective of the fluffy.
I would agree that the difference is mostly academic or philosophical in nature though - if it looks, smells, feels (literally and emotionally) and screams like a real animal, for all practical intents and purposes, it’s a real animal.