Because of the extensibility by allowing users to install additional plugins. You can also add / change themes, customize settings according to your programming taste and many more.
This aims to provide just the tools a developer needs for a quick code-build-debug cycle and leaves more complex workflows to fuller featured IDEs, such as Visual Studio IDE.
I am actually not a coding person, but I did code for a while. I love VS code for its simple user and aesthetically appealing user interface. Also, it can be well integrated with Jupyter notebook to run DS codes, which are important for me because I mostly write codes for DS. My boyfriend, a prospect software engineer, also enjoys writing codes with VS code.