I like CSS grids for global layout stuff because of the layout flexibility it gives you when it comes to different screen sizes and orientations, without having to use js when you need to swap the order of things around (and at some point you will have to eventually unless it is a very simple page). This helps separating the markup from the styling even further so it is rather a good thing.

I would — however — never had the idea to abuse it like that. Why not just limiting using max-width on your text-related tags?

The only problem I ever had with that is that markdown generated HTML will wrap <img> into <p> if it follows the standard and as of now there is no CSS way of selecting p without child of type IMG or p only with child of type img..