"Backup and Sync" still misses features like Files On-Demand/Smart Sync available in OneDrive/Dropbox and deleting files online pollutes the local trash/recycle bin on macOS/Window computers.
"Drive File Stream" actually has these lazily loaded file placeholders, but it is treated like an additionally mounted volume instead of a local folder somewhere on my local disks. It also managed to occupy over 60 GiB RAM for over a week during its initial sync which had lots of small files created by Arq Backup.
It seems like 'unlimited' cloud storage is foremostly limited by the performance characteristics of their sync clients.