Storage
Use the Storage menu to see which external storage devices are connected to the router. You can unfortunately only format them into EXT4 and FAT32 filesystems. However, if you have a device that has already been formatted in NTFS, it will be recognized properly by the router.
You can also set access permissions to external storage devices.
Should you enable write-cache support, you will notice a small increase in write performance. This feature is only applicable to devices using the EXT4 filesystem, though, and you might lose data if such a device isn't removed properly.
Privileges
Synology put its NAS experience to good use when it came time to develop SRM, so you are easily able to create shared folders on a storage device connected to the NAS, or assign it user permissions. You are also able to create user groups and set a few password-strength rules; 2-step verification is also supported.
File Services
If you want your router to be discoverable to Windows or Mac clients, or be able to share files, you will have to either enable the Windows or Mac file service feature.
Like in Synology NAS servers, there is a media indexing feature in SRM that can automatically scan for multimedia files and index them accordingly.
Hibernation
Use these options to set your HDDs to hibernate after a certain period of time to save some energy and reduce how heavily your HDDs are taxed.
Printer
You can add a network printer through this menu.