With web-based editors, both teammates need to use the same web app to get collaborative benefits, which may not be their primary, day-to-day editor. Many web-based editors assume that you are building and deploying into a Virtual Machine often hosted in a cloud environment.
While this may be desirable for many scenarios, developers often want to collaborate on apps that aren’t hosted in a VM or in the cloud. With Live Share, you and your teammate can use the capabilities of the tools’ ecosystem in addition to the same capabilities available in web-based editors.
Live Share goes a step further and enables you to share a debug session. This makes it especially useful in enlisting others to help you track down issues that only happen on your machine without altering their development workflow or needing to alter the application design.