I read your question about the smallest organism, and I was wondering if Prions, single protein pathogens, could be counted as organisms since viruses are.
Scientists still argue over whether viruses ARE organisms.
However, reproduction in this way is different from classical biological reproduction in that it can only produce 'offspring' from already existing akind. And there is no nucleic acid involved in their life cycle. That is the major distinction with viruses. I had a discussion with a geologist once who described how chrystals are produced from minerals dissolved in fluids. They form to a regular shape and pattern, and the way chrystals grow is similar to biological growth in some respect.