WYSIWYG (a.k.a HTML Editor) has become a De facto for quickly formatting and publishing contents from dynamic site like Drupal. This is certainly a time saver and prevents from getting hands dirty with HTML.
In this connection, CKEditor has been a pioneer and around in use and development cycle for a decade (first release was on March 2003, in the name FCKeditor).
Simplenews is one of the solid Newsletter management modules for Drupal. It allows a Drupal site to have multiple newsletters at once, nodes can be sent out as newsletter to multiple recipients on a single cron run. It plays well with HTML emails as well with Editors like WYSIWYG, Drupal mail system and other contrib modules like Mime Mail. Besides these, it allows to have specific sender name and email address per newsletter.