The changelog suggests it was added in March, so yeah fairly recent.
In my opinion it would probably be better to keep it separate. The very nature of it (providing a backdoor to a discourse instance) is a potential security risk if not handled correctly, so it’s probably better that it’s only installed on those instances that really need it.
Also I think the slack API scopes required (links:read and links:write) are completely different to that of chat-integration, so there wouldn’t be much effort saved there by combining them.