It looks like Gutenberg does three things:
1)It shows the code scaffolding for PHP+JS [it indeed looks like React.js wins] on WordPress.org;
2)It has the makings of a WordPress PageBuilder thus confirming the ascendancy of frontend driven WYSIWYG page/post/CPT design in all Website Development, not just WP;
3)It will certainly shake up the Visual Edit and PageBuilder plugin marketplaces.