Imagine inserting a Paragraph block and choosing that sky blue from your theme as the block’s background. Now, imagine doing this a few hundred times only to have it disappear a couple of years down the road when you want to switch designs.

Have the blue background just disappear isn't ideal in this situation, but neither is keeping it. What happens when someone updates their brand color scheme and that sky blue - from a theme or from the default gutenberg color options - has been added hundreds of times? If the website lasts longer than five years, the user will probably want to update the look at some point.

This is why mixing design in with content and then saving the settings of every block separately in the database is a mistake. We're practically back to html font tags. React was not designed for this either, CSS and html were supposed to mix together, but the data layer was supposed to be separate.

It's one thing to give users an option to override defaults and take things into their own hands, it's another to put every user in the position of having to make design choices and then get locked into those amateur choices because it's too much work to update hundreds of blog posts.

If I'm missing something here, let me know. I'm still astounded that the system was designed this way.