If your blog is just a personal diary, then it doesn't matter that you have no traffic and no one else interested in your writing.
But blogging is about sharing with others, and I'd say most bloggers like some followers, and commentors, even if they are mostly friends and family! A blog could just be a way to keep in contact with family around the world, about family things, that no one else would be interested in, so traffic wouldn't matter.
It shouldn't be the be all and end all of blogging. After all, traffic doesn't always mean people have actually read what you have written or enjoyed it. Comments and likes and followers mean more I tihnk.
Thanks, overmydeadbody. The styles are all so different, aren't they? I think my blog is going to be more informational, with perhaps some commentary, rather than 'share this experience with me', so I guess it's the kind of thing people might dip into when they need information, then come back to later.