If you have multiple backlogs, which one does your team know to pull through?
How do they know which one is prioritized higher than the other?
How do they know which items that cross backlogs might be different than the others?
Keep your backlogs simple so that when your team starts to pull from them, they know they are pulling from the right place at the right time, working on the right thing.
Essentially what a backlog is supposed to do.