What is the main advantage of using a wysiwyg ("what you see is what you get") editor when constructing a website?
only one programming language is required.
websites may have more professional construction.
knowledge of html is not required,
website templates are not necessary.

The main advantage of using a WYSIWYG Website development to done by profession construction.

Websites may have more professional construction.

Explanation:

On developing the web pages for web site it depends upon the content and business requirement. Normally web page can be classified either static web page or dynamic web pages.

Static web pages with is content of picture or gif and images and only static content display varies dynamic web pages will display content  of picture or gif and images.

Also expect input from end user such as customer registration form or service request form or knowledge share and posting comments and downloading the some useful document or content.