It's because OneDrive for business is a completely unrelated tool under the hood with no relation to OneDrive except a deluded manager somewhere feels responsible for both.
Same with Skype and Skype for Business.
i'm not sure about the manager. skype for business doesn't have pretty much anything in common with skype except the name and icon...
Even the executable is still lync.exe for Skype for Business.
rclone is great. Thanks to its use of multi-threading you can download and upload pretty much at line speeds. It would be even better if it provided file-delta type operations, but maybe this is a limitation of OneDrive itself.
I really should put some time aside to write a script I've been thinking about:
1) Poll [somefolder] every 10 seconds (or whatever). Or watch with inotify.
2) On change, wait [5 seconds] and if change remains the same...
3) `borg create [oneDriveRepo]::[somefolder]` (does a delta backup with deduplication and lz4 compression, can be FUSE-mounted, and can be encrypted).
4) rclone -> [oneDriveRepo] -> onedrive.
And the reverse in the other direction I guess.
Like this tool it doesn't support One drive for business though. Microsoft have made it very difficult for open source programs to use one drive for business as far as I can see. It has the most complicated registration procedure I've ever seen - even Microsoft admit it is too complicated!