That's one way to look at it, but with sufficient effort on the quality of the host filesystem, you can offer better reliability, and offer features that are ex

That's one way to look at it, but with sufficient effort on the quality of the host filesystem, you can offer better reliability, and offer features that are expensive/difficult to do properly from inside a VM. Streaming transaction logs and snapshotting (and if you're adventurous, deduplication), for example.