According to its documentation com.xpn.xwiki.api.Object#get(String) is like com.xpn.xwiki.api.Object#display(String, 'view').
This method's name is misleading since it doesn't return the Object's property value; it"s equivalent to display(String, String) (with type equals to view).
But it behave like com.xpn.xwiki.api.Object#display(String).
In the attached screenshot, a TagClass object has been created, and get called on its tags fields from its title and its content. The screenshot shows the result in Wysiwyg edit mode.
Expectation would be to see the tags displayed, not to have an input box if the javadoc was true