The short answer is NO!  This upgrade is a major change in functionality.  It is not just a bug fix or security patch.  So especially if you have a live website and have a choice about upgrading, please wait.

The new WordPress editor is called Gutenberg and it is meant to give the user some more editing power.  Before 5.0, most developers would use powerful builder themes or plugins to layout their pages, such as WP Bakery or Divi Buider.  Now potentially, we could do the same thing without heavyweight themes or plugins.

Why might you want to upgrade today?  If you have a staging website and want to try out the new editor.  So you know, the Gutenberg editor has not been well received by the WordPress community.  It has a 2.5 star / 5 star rating from developers who have tried the plugin.  I generally wouldn’t install anything with less than a 4 star rating.

Some webmasters may not have a choice if their hosting upgrades automatically.  Most likely your website would still run well.

When should you upgrade?  Security fixes will still be performed on the 4.x and 5.x versions of WordPress, at least for now.  So wait to upgrade to 5.x until you need the new functionality.