I can see why someone would prefer Typst over LaTeX when the source is written in Typst or LaTeX, but what are the advantages if your source document is in Markdown? Is there anything else beyond the (presumably) smaller install size of Typst?
When compiling the Markdown to PDF, you might want to customize the PDF template. That's arguably easier and more pleasant to do with a Typst template than a Latex template. Also the compilation with Typst is often much faster.
Typst is 2-3 orders of magnitude faster than latex, which for book-sized projects can be the difference between a minute and sub-second compilation time.
Something I found useful is that you can create a much more minimal pandoc template for typst than for latex. Obviously if familiar with latex it probably won't be an issue, but when I tried to make my own barebones pandoc template (i.e., stripping out beamer) I gave up.