In simple words, text check point verifies entire text in the object where as text area CP, veries text only in the specified region(done through dragging mouse) in that object.
You can have any number of text area CP But only one Text CP(though you can have duplicates all doing same task) on an object
You can have any number of text area CP But only one Text CP(though you can have duplicates all doing same task) on an object