> Is this increasing complexity in the Web layout world worth it?

Yes. I held off learning about CSS Grid for a very long time and as soon as I did I was converted. Sometimes I think the web doesn’t get enough credit for its ambition: mobile viewports, desktop viewports, touch interaction, pointer interaction, complex documents, webapps… it’s a lot. But you get some complexity as a side effect. The complexity we do see these days isn’t invented out of whole cloth, it’s standardising and improving layouts people are implementing with JavaScript, often badly.