Then they'd have her stay in longer to keep Bernie from winning Michigan and other critical northern Midwestern primaries too. Although Biden winning Minnesota was telling.
I'm hoping she'll give the DNC the finger and endorse Bernie, just to keep the chaos going, and to weaken Biden. It'll be interesting to see how much Leftist vs. Establishment loyalty she has. Although the "You called me a liar" kerfuffle she started might make that difficult.
I'm guessing she's waiting for one of them to make her an offer for VP slot, or at least some other cushy gig, before she endorses anyone. Bernie is much more likely to do so than Joe, so you'll probably get your wish.
Though, like you said, Bernie may still be pissed over how she tried to sandbag him, so it's possible Biden will make her an offer for a less important slot while Bernie doesn't offer anything. I don't think that's quite as likely, though, since Bernie is probably going need Warren's delegates to get him anywhere close to being over the top.