I don't think there are direct consequences from YouTube themselves since they can sometimes block comments on videos such as videos not meant for children but not properly labeled for adults.
As for pros and cons I think at its basic there are no real pros I can think of. Why would you not want ppl chatting on your videos, giving thoughts and opinions on the content? Chatting not only helps you learn what is working and what isn't on your videos, but it also gives you a chance to interact with your audience, get them to come back for more. Viewers often like creators who interact with them. Being a YouTuber to an audience is like being a movie star or musician who is often an average Joe like them who will also interact with them. You get the status and they get the connection movie stars and musicians can't give their audiences.
Now, if the reason you ask I because you're concerned with managing the chat then there are features both on YouTube and TubeBuddy you can use to help you. It's a matter of familiarizing yourself with these features, setting them up and tweaking them to your liking and maybe even getting moderators (friends, family, etc) to help.
Hope this helps.
