Are there any user cases how these iTwin services are used in existing workflow?
We have had users share the iModel on the iModelHub with other participants on a project which can be viewed in any browser for review, with it either be on a tablet, phone or laptop. We've also had other users, once the data is in the iModel, run clashes and view change sets between what was new, modified and deleted. Once the Design Data is in an iModel on the iModelHub, you can take advantage of the iTwin Services available to you.
Also, if you have Civil3D files or Revit files, you can synchronize this data to the iModel as well with the iTwin Synchronizer to view on the iModelHub.
With the the release of MicroStation CONNECT Edition Update 14, the option to synchronize with the iTwin Synchronizer to an iModel will be integrated.
Do you have a specific workflow you are trying to incorporate?
There is not yet a existing workflow but just based on marketing newspeak it is hard to understand how it really works together. iModels, iTwins, BIM are just a concept or vision for which a real workflow need to be assigned. There are costs associated by doing BIM or iTwins and these needs to outweight these costs. Of course not doing BIM also costs but it is harder to prove the opposite.
The workflow we see it needs to be implemented is construction project: