Yes, you can use dist-update (?), but generally it is recommended doing a clean install each time. Now, as for the need to install a new version, it is only if you, like me, are suffering from the well known decease of having to run the latest at no matter what cost. Many people tend to stay at a version they are comfortable with and they find stable, but hopefully Elyssa will get LTS (Long Term Support).
I prefer a clean install each time I update, but some has used dist-upgrade with some success, some have had troubles with it, and I think you will miss out on the newest artwork as well