Yeah, they are very different things. One is for text/inline flow and the other block flow. As a fan of CSS Columns (multicol) I hope that the interaction between Columns and Grid gets better standardized. (In my case I wanted better support for embedding Grids in columns; my tests worked in everything but Firefox. So it is interesting to me that Firefox seems the most interested in pushing multicol forward as a standard [1], since it stopped being a Trident/Spartan priority when Windows 8.1/10 abandoned multicol as a key UX principle of Windows 8 apps.)

[1] https://hacks.mozilla.org/2019/11/multiple-column-layout-and...