I've heard the Pinot is for "User-Facing, Real-Time Analytics" and was wondering who the "User" is in this context? Is it referring to external end-users? If so, is Pinot overkill for internal analytics?

The user can be various personas including your BI folks, your customers and your customers' customers. This is the good part about Pinot that you can use it for this wide spectrum of use cases

That's a really great question, Robert!