You had two instances because there are 2 versions. Smart Lighting (old) and Smart lighting, with a lower case L, is the new version. Given that it just came out, and is redesigned for the new architecture, it makes sense that it will be around for the foreseeable future.
See this post for more info:
https://community.smartthings.com/t/smart-lighting-new-plugin-version/251409/1