Wireframes are used to block off space in the early stages of design. They can be deceptive because folks either get married to the wireframe being the Word of God or in contrast, too vague. 

They can be used to show actions, space allocations and offer layout and behavior insight before the concept is sent to be formally designed and prototyped. 

The above set of wireframes was created by me in Adobe Illustrator as a first version for a candidate matching application called MedMatch.