tl;dr is yes (to your last question). The longer answer is that this is about how to logically think about the semantics of computation using a declarative API

tl;dr is yes (to your last question). The longer answer is that this is about how to logically think about the semantics of computation using a declarative API, and the actual physical execution (e.g. incrementalization, record at a time processing, batching) is then handled by the optimizer.