It's lazy and not as useful to later users to just punt to chat, and it tends to go down the path of "localized answers to localized questions" instead of "general answers to general questions".
Forcing it to remain in the context of the question/answer paradigm of Stack Overflow means that the information is retained and semantically indexed for folks who may have the same problem in the future. Taking things to chat, while quite possibly being a more efficacious way of addressing the specific problem does a disservice to future folks who may have a very similar problem that could be answered with a good generalized question.
Punting to chat also has the downside of not rewarding the answerer or asker with reputation, which is how our community determines privileges. It's important to realize that it's not just the answerer that loses here because if you give them the answer in chat, they cannot accept it (+2) and it may mean the quality of their question suffers whereas the give/take by answering/commenting/editing could result in a good question that will reward the asker with reputation and badges, thus encouraging their continued participation and contribution.
Chat is useful for sure, but it should not be used as a mechanism to replace anything that Stack Overflow (or more generally, Stack Exchange) is already set up to do.