This is the reason I don't mind Warren staying in the race, even if she pulls some votes away from Bernie and drops attacks on him occasionally. She's still fighting for progressive values, spreading a progressive message, and is going to hit the centrists harder than she hits Sanders.
As strong as she is in debates and as strong the feelings are in her base, I'm leaning back towards Bernie picking her as VP being the best move electorally. It's the best way to pull in all those people complaining about "Bernie Bros", it's the best way to keep women on the liberal end energized, it deads any claims that Bernie doesn't have clear enough plans or isn't being realistic, and she'd destroy Pence in the debates.