Hello Brian
According to the exam topics for the CCNP ROUTE exam, BGP route summarization is not explicitly mentioned. However, it does affect individual route BGP attributes, and this is important to know. For example, when the aggregate-address command is used, the AS_PATH among other attributes, is lost.
Ultimately, it is great to know because when you work with BGP it just add one more parameter that you can “play” with when configuring a production network. It may not be that important for certification purposes, but more for the real world usage of the protocol.
I hope this has been helpful!
Laz