Pros: Reaches a wide audience that may not normally be "readers." Encourages innovation, and experimentation. Makes poetry a part of daily experience. Allows for beginners and experts to create, and let the audience decide. Gets rid of gatekeepers that try to dictate what real "poetry" is.
Cons: Often encourages and rewards trite themes. More difficult arena to present more "complex" themes. Makes people wonder why they paid so much for MFA if this is poetry.