Personally, I wouldn’t use that folder - it’s the local Root folder for your account - and it’s not enabled for Network Sharing by default. Did you explicitly change the properties of this folder to add Network Sharing to it?
If you make it a Shared Folder then the entire contents of all the folders (documents, pictures, videos, etc.) in your user account are accessible over the network. Admittedly, they are protected by your username and password, but still…
Far better to follow @Rugby 's advice and create a local Windows account and use that for a Shared Folder for your Backups.