The dollar sign indicates that the share is 'hidden' and can't be enumerated by traditional means. The C$ share is created by default and provides root level ac

The dollar sign indicates that the share is 'hidden' and can't be enumerated by traditional means. The C$ share is created by default and provides root level access to the system drive, and is locked down by default for this reason you are correct that they are just SMB shares like any other. They can be removed, though many management processes across different applications assume that those shares will be present