Actually, it's worse than that. Time machine's "snapshots" aren't snapshots - they don't represent a point in time at all. A time machine backup can complete

Actually, it's worse than that. Time machine's "snapshots" aren't snapshots - they don't represent a point in time at all. A time machine backup can complete and nevertheless be unrestorable. On filesystems that support snapshots - including Windows' - you can actually do a reliable backup, but not on OSX.