If you're not burning wood and your stack drafts properly (proper height etc. ) the last thing you want is a stainless liner. A tile liner is not only to code, but is far superior for coal or oil, even if it has a few cracks in it.
The stainless liner salesmen have successfully caused everyone with a masonry chimney to be scared. Unfortunately, the people doing truly unsafe and stupid things that WILL burn their house down are going to keep doing them.