Pros of same-team: fewer ideas "lost in translation" between data scientists and data engineers, better understanding of which datasets/flows are top priority, can sometimes share some stack components and help datascientists improve their code, better chances of getting data scientists to contribute their own batch jobs (there's just more trust as opposed to dealing with some "engineering" team that is less connected to you)
Cons of same team: data engineers may not be as in-the-loop on what's happening with production datasets, may not be as tightly integrated with a devops team, may get overly caught up in "business logic" as opposed to "plumbing".
I've never understood why data science teams are typically so far removed from "normal" engineering teams. Maybe it's the DevOps kool-aide speaking, but in my opinion, teams should be more horizontal than vertical!
When it's two independent teams, you tend to get a more research focused Data Science organization and a team of engineers more focused on plumbing.
Which option is better will depend on the organization goals. If you think that you have a straight research problem than a dedicated research team is useful. If you want to ship product than one team is better.