What is the difference between WYSIWYG Web Builder and WordPress?

WYSIWYG Web Builder is a desktop application, you can install it on your computer just like other desktop software. You control where your files are stored. You can work on your websites even when you are offline and only need to go online to publish the website.
Wordpress is an online content management system which must be installed (and maintained) on a web server.

Wordpress is 'free', but it has hidden costs. Many things in Wordpress (like seo, performance, ecommerce, security) require a plugin or an add-on service. WYSIWYG Web Builder is not free, but has everything your site needs built-in

Wordpress websites are generated dynamically from a database, the page is rebuild every time a user visits the website.
Most WYSIWYG Web Builder pages use static HTML which loads much faster. Only advanced features (like protected pages) require a database. But even then, the database requests are kept at a minimum. If you just take a quick look at the HTML in the browser, then you will notice that the code is much smaller and cleaner than WordPresses "spaghetti code".

WordPress is the most hacked CMS. WYSIWYG Web Builder sites are more secure (and privacy minded).
Standard pages (without forms) use static HTML which cannot be hacked. But also for more advanced features that require PHP, the code is usually so simple that anyone with a little programming knowlegde can understand what is going on.

A common complaint about Wordpress websites it that they all look the same, because Wordpress is template based.
WYSIWYG Web Builder also supports templates but you can also create layouts from scratch!
You have full control over the layout which allows you to create unique designs!