I believe the reference is to the Bountu sensors, Claude, Ririn and the other.
Why are they there? Because it wouldn't make sense if they just suddenly disappeared forever. Think about how dorky BT2 was about it. Watch what Vegita does at the end of one of the stories -- he just flies off into nowhere without anyone noticing at all, because in the storyline he's not supposed to be with the other characters, but the movie placed him there anyway.
There's nothing wrong with the Bounto story, other than maybe they deviated from the story so as not to surpass the manga in speed. It was a helpful character development, because it developed the history of several characters, including, Zeraki Kenpaichi (because let's face it; we haven't been privy to much about him so far). It also tells us that Genryuusai, while ancient in appearance is not as old as he seems (as he wasn't the Seireitei Captain Commander 500 years prior).
And of all the ways to handle deviations, it's still better than doing: episode, episode, FILLER, FILLER, FILLER, FILLER, episode, FILLER, FILLER, FILLER, FILLER, episode, etc.
Especially when each filler is completely ignored in the next actual story episode. Rather than do a bunch of fillers that go here, there, everywhere, and don't mean anything from episode to episode, they handled it much better, and created an actual story arc.