[spartanatreyu]

Because if you're relying on server-side software to process your finished product, then your finished product is vulnerable to dependency rot and overall general software rot.

But if you process your markup at build time into it's finished HTML, then you can host it anywhere - anytime and it'll work.

[chrismorgan]

I think you misunderstood the comment you’re replying to. Its proposition is: you’re already doing a build process for Markdown to HTML, and even perhaps adding some preprocessing on that, so if you’re only using Custom Elements as a simple template engine, why not apply that in your build process too, and emit more reliable plain HTML?