I actually think CSS Grid solves your #2. A lot of people who don't use grids were probably overwhelmed by all the grid libraries out there and the complexity and overhead of them. I made my own grids, if you could call them that, and then Flexbox showed up and everything became amazing and easier. Then CSS Grid showed up and said "You think Flexbox makes amazingly easy responsive layouts? Hold my beer."

I might be a grid-noob, but let's take a super-duper common situation:

I want to left align one element and right align another, keeping them in the same row.

Flex makes this very easy:

    <div style="display:flex; justify-content:space-between">
      <div>Left</div>
      <div>Right</div>
    </div>

Does grid also make this easy?

As another grid-noob, I thought I'd try to tackle this one. It seems to require only one additional style to define the grid:

    <div style="display:grid; grid:auto/repeat(auto-fit,minmax(min-content,0)); justify-content:space-between;">
      <div>Left</div>
      <div>Right</div>
    </div>

There's one gotcha: repeat() doesn't seem to accept min-content as its own value, so I had to use minmax(min-content,0).

It's strictly less effort to do this with flex, but I expect that as soon as you have more than two single-word divs as children, Grid becomes more useful.