Agreed that it’s pretty cool. The vast majority of on-stage demos like this are faked, but it’s not usually because they aren’t long enough into development that they just can’t do it any other way. And as long as what they show is what you get, which is the case here, I think it’s fine.
I haven’t used or know much about the onedrive cloud desktop, but would mega work for you? I use mega for all my cloud storage with auto syncing, and you can choose whatever folders you want to be synced. Free is 20 GB, and what I use is 2 TB of storage and 2 TB of monthly transfer for $10/month. They use use zero-knowledge encryption. Here is more info, including their security whitepaper if that’s of interest: https://mega.io/security
I’ve used it for close to 10 years now and am very happy with it, never had any issues.
Sorry if that isn’t what you’re looking for, but hope it’s right!