Gutenberg block editor on WordPress: a new blogging experience

Wordpress has rolled out Gutenberg editor with Wordpress 5.0. It is the default now, and one can go back to the classic editor by using a plugin.
I had announced the likely introduction of Gutenberg editor, long back. Wordpress has kept its promise and with Gutenberg, added a very useful property to blog/ website editing: blocks.
The block editor on Wordpress is applicable for both, posts and pages.

What is block editing of websites?

If you have been using Blogger or the older versions of Wordpress, the text editor window looks like a word processor (e.g. MS Word). There is a spacious single slate on which you write. You can format the text using the formatting toolbar, add image and so on using their own tools. 
In block editing, which is available in Wordpress 5, every element of the post is a block. So, there is a title block, each para can be a separate block, a list or a table is a block and each image is a block too. 
A block is like a stand-alone tile in the floor layout of the post. 

How does block editing enhance editing posts on a website/ blog?

If you consider each block as a floor tile in the post layout, it is obvious that one can easily re-position the tile/ block without disturbing the entire layout. One can also replace formatting of an individual tile/ block more cleanly. 
The beauty of the Wordpress block editor is that you can add one of the many types of pre-designed blocks such as paragraph, table, list. Each block comes with its own tool sets that match the type of block. You can drag a block up, down or side-ways to re-position it. Blocks also make it possible to create multi-column text.
Gutenberg block editor for Wordpress

One fantastic option on Wordpress is to create reusable blocks. Once you create a paragraph or list or some other element that you would use later too, you give it a name and save as reusable block. The next time you need to insert the same element, pull it from the list of reusable blocks created by you!
Since the block editor comes with a number of elements that needed plugins earlier, the task of adding such elements becomes a one-click affair. For example, you could add a button, a text+image box, a cover image. 
Bloggers and website creators who have mastered advanced features of Wordpress can make use of blocks in more imaginative ways, with blocks of codes etc.

Is the classic editor on Wordpress gone? What about plugins that may not work well with blocks?

There is a possibility that some people may not like the block editor because initially it may look slightly confusing. Moreover, there could be some plugins that do not work well with blocks. 
For such situations, Wordpress has created a plugin, Classic Editor Plugin, which restores the classic/ old-style editor.