From the perspective of the disk access, this is where you will definitely win at least a couple of times with the amount of the disk access while processing the information, amount of memory that you will need to store and process (think hashing and sorting for the late materialisation phases), and you will pay less for the occupied storage.
Another noticeable thing was that the memory grants for the Indexed Views query was smaller compared to the query that was processing the original columnstore table FactOnlineSales.
Clustered indexes are currently not available as an option; we’ll see if that changes in the next version of SQL Server.