I believe this sentiment is wildly popular and will grow between now and 2020. We are not going to get the best nominee, we're going to get the nominee who has the best chance of beating Trump.
I'm undecided, but honestly I might be tempted to vote for Beto for that reason even though I like Warren more on policy.
He did a good job actually turning out voters (especially millennials) last election and getting a lot of Dems elected in Texas, and turnout is what it'll come down to.
Obviously I'll vote Dem in the general election but Biden's only real appeal is that he's nonthreatening to old white people. I don't really see him turning out voters like that.