Why tableName() is declared as '{{%something}}'?

In Yii 1.x activeRecord descendant’ generated tableName function returns a string using

return '{{table}}';

versus Yii 2 version:

return '{{%table}}';

What’s the added ‘%’ sign for?

In yii-1 will be added table prefix before table name.

In yii-2 you can add table prefix in any place…

return '{{biggroup%sometable}}';

using prefix "hello" will be "biggroup_hello_sometable"

So ‘%’ is the placeholder for tablePrefix.

Why has Yii dev team developed this feature? What’s the added value?