Since the Key is held on the Hub, why would you bother to keep the data on the Satellite as well?
Isn’t this duplication?
Therefore, by definition, holding the same data on the satellite is redundant.
However, in practice, keeping the Source Key on the Satellite has a number of benefits.
Primarily, it enables traceability of the data. Tracking down data issues and fixing them becomes more reliable and simpler.
In addition, a query developer will often be able to jump directly from a link, to the required satellite, without joining to any Hub. In this case, having a full set of data available is a benefit.
By default, ODE does not eliminate Key data from the Satellites.