You've still got to deal with the fact that some browsers support some aspects of CSS Grid, some you have to fall back to Flexbox which doesn't work in the same way and you'll still use some grid system based around floats or display:table to capture everyone. More choice of ways to do the same thing, some very useful media queries, but most of the rest of it could have been done equally hackily in the late 90s.
If IE6 was bad, the fact that we're on the third or fourth generation of different implementations of CSS layout aiming to reproduce common layout styles achieved with HTML tables in the 90s and still need javascript polyfills to use them on non-autoupdating browsers still in widespread use is ridiculous
I'm intentionally not learning CSS Grid until it has good browser support. That way I only need to keep one thing in my head at a time, and I don't need to write a bunch of fallbacks. I did the same thing with Flexbox.
