I'm watching Blood C, and I'm reminded that in anime, dialog can often consist of characters just saying other character's names. In this example, most of Tadayoshi Kisaragi's lines towards Saya are just her name. If I recall, there was a similar situation in Blood+.
This is also epitomized by Mocha and Tskune in this scene.
Is this an anime thing, a Japanese thing, or a more common trope of some kind? Western live action media doesn't contain this phenomeon, so I think it's an anime or a Japanese thing.
I'd hazard a guess that this is the voice acting equivalent to non-sakuga animation (sakuga explained by Gigguk) mean to fill dialog cheaply.