I definitely learned flexbox and thought to myself "this is good enough", and haven't really pushed myself to learn grids. It does seem like there's some reason to prefer grid [0], but it overall I've never needed to do anything that can only be done with grid (except data tables, for which I use actual tables).
I've only used grid for responsive image galleries like https://labs.jensimmons.com/2016/examples/image-gallery-grid... or responsive cards like https://every-layout.dev/demos/grid-cards/. `grid-template-columns` is good to learn. `grid-gap` is convenient. Flexbox seems to handle everything else.
But I'm still iffy about grid template areas. The article makes a case for easily adjusting layouts per breakpoint, or "for team members who might need to change a layout." Maybe I'm just not the target audience.
But what’s nice about it is that, if you want them, grid areas are extremely declarative. With non-area templating, you are defining the layout based on the items, and that can be challenging.
https://caniuse.com/mdn-css_properties_gap (no IE 11 support)
Nothing stopping you from using both as necessary, combined it's a very strong layout tool