I don't particularly like this style because it tends to interrupt the narrative flow of a use case. This makes it harder to read, thereby losing some of the advantages espoused for the use case approach. This has both advantages of clearly identifying each event and corresponding response while preserving the narrative flow. There are many guidelines that we could discuss on writing and formatting use cases. Rather than deal with each, I refer the reader to the example use cases.
Active voice is easier to understand and greatly improves the clarity of narrative.
Passive voice obscures the active object. The reader must make some effort to reinterpret passive voice statements to decide whether the actor or the system is the active object in the sentence. Mis-interpretations do happen in the heat of systems development, so we should do our best to avoid them. I recommend using the grammar checker of your word processor to look for passive voice sentence structure in your narratives. We have become so accustomed to encountering this oblique form of communication in technical writing that you would be surprised how often you use it, even after making a conscious effort to avoid it .