A WYSIWYG is basically What you see is what you get. This means that you have the formatting Tools on the editor to add whatever text based formatting you want such as Bold, Italics etc. It's basically a formatting editor.
The single line is an editor for plain text. There isn't any formatting tools on this editor and is basically used when you want to store raw unformatted texts.
My question was regarding multiline and WYSIWYG. But the use case for SingleLine, MultiLine and WYSIWYG would be helpful. Are there pros/cons to using one over the others ?
You will use the WYSIWYG editor whenever you want to allow for formatting of the text that is being stored on the site.
For the Multiline it is used when text formatting isn't a factor. Lets say you want to add some additional notes on the post , in this case you will use multiline.
The single line is when you want to add some short text.
Additionally its much easier to evaluate the single line fields and multiline fields in our conditional blocks. They can be interchangeable but what will determine the usage is if you want to be able to visually format your texts or not.
When it comes to pro/con I can only think of what differentiates them which is the ability to format your texts visually on the WYSIWYG editor.
Also it should be noted that if you're adding shortcodes to you posts it will only work when added to a WYSIWYG editor given that this field is processed by PHP while the others take the raw text directly from the database.
