I do not like to have discussions in chat because of how unstructured they are. Important details get lost and can never be hard to recover. Furthermore github comments are an excellent place for seeing different aspects and workarounds for an issue that has not been fixed. They also often show inner structures of the program that can be hard to gasp from the code itself (why x has been done this way instead of that way).

While chats can be used for that, they do not make a good job to archive the results a group discussed. For open source projects, this is essential. I often read 1 year+ old issues and they discussions are still accurate and good.

When people chat, they do not have a lot of discipline to document this. Chats are more like a conversation. They are great for two or more people to discuss something but not really good for an outside person who just gets to read the protocol.

SO is not the place to have discussions. You help people for their specific problems. You do not discuss changes there. At best, you leave a link to the issue tracker which deals with that topic.