There are two ways to publish here, and you can mix them freely.
The browser editor
Go to /admin on your live site. Sign in with GitHub, write a post in the visual editor, and hit publish. Behind the scenes it commits a Markdown file to your repository, and your site rebuilds automatically. This works on a phone, which means you can publish a thought from a train, a queue, or a hotel lobby without opening a laptop.
Plain files
When you are at your desk, you can skip the editor entirely. Add a .md file to src/content/blog, fill in the frontmatter, write, and push. Same result.
When you want something interactive
Rename a post from .md to .mdx and you can drop a live component straight into the prose, a small chart, a calculator, a working demo. The rest of the post stays ordinary Markdown. That is the one real advantage of this setup over a plain blog, and it costs you nothing until the day you want it.
Keep the writing first and the machinery quiet. That is the whole trick.