I found my answer after further research on a Microsoft KB :
During installation, most of the core IIS components and configuration files are placed inside the %windir%\system32\inetsrv folder. The Inetsrv directory is considered the main installation directory for IIS. It has been reported that some non-Microsoft security scanning tools suggest that IIS should be installed on a non-system drive for security purposes. This is not a correct assessment. IIS is a core Windows component and cannot be installed on a non-system drive.
There have also been reports of suggestions to move the Inetpub directory to a non-system drive for security purposes. The Inetpub directory is the default web content directory and also acts as a placeholder for logs and temporary files.
Most of the Inetpub subfolder locations can be reconfigured based on your needs and business requirements, however the initial Inetpub folder and subfolders should never be renamed nor deleted. This is because Windows Servicing may at some point need to update one or more of the core IIS files that are stored in %systemdrive%\inetpub. Moving the Inetpub folder structure completely off of the system drive is not supported.
https://support.microsoft.com/en-us/kb/2752331