In reply to Elsie G.

I don’t think this update is just bells and whistles. They are literally discussing a customizable sidebar, which reduces the need to install a plugin just to do just that.
By the way, Gutenberg is just a name for a project that aims to modernize the WordPress core. In other words, it is the core. If I remember correctly, they don’t want to provide support for “classic features” after 2024.