Do I need to re-write my whole blog in Org?

If you are considering to try out ox-hugo, and if you have already been using Hugo, it is normal for this thought to cross your mind:

I already have dozens or hundreds of posts written in Markdown. Do I need to convert them to Org if I want to start using ox-hugo?

The answer is No.

This package will export your future posts written in Org to Markdown. And those files will live along with your already written Markdown posts. So converting existing Markdown files to Org would be purely the user’s choice, your choice – but that’s by no means a necessity if you want to start using ox-hugo.

.. And if at some point, you want to stop using ox-hugo, you still have the exported Markdown files.