"Add shortcut to OneDrive" Vs "Sync"

Inside any SharePoint online document library, we have 2 options: -

1. Add shortcut to OneDrive

2. Sync

But I am not sure what is the exact differences between the 2 options? for example in my case i am syncing the library using OneDrive application and using the "Sync" option + I have my one drive personal site synced to my machine using OneDrive application. So when i am using the "Add shortcut to OneDrive" the library will be synced to my machine similar to how the "Sync" work. so what is the exact differences between the 2 options? and why Microsoft recommends using the "Add shortcut to OneDrvie" over using the "Sync" option? In other words, at the end if our one drive personal site is synced to our machine, then the 2 options will add the files to our machines..

Thanks