1. Most Sanders supporters are not leftwing purists or so called " Bernie Bros." The vast majority of us will vote for Biden in November. This includes Congresswoman Alexandria Ocasio Cortez and former Labor Secretary in the Clinton Administration Robert Reich.
2. Bernie Sanders is assertive, consistent, and principled. Too often he's wrongly labeled by opponents as unwilling to compromise or difficult to work with. I disagree with the critics. He stands his ground and fights. Sanders unlike so many Democrats in Congress understands that compromise and negotiation come out of struggle. They are don't come before it.
3. Joe Biden has serious drawbacks. He's not consistent in debate or a compelling speaker. Moreover Biden can't make this a popularity contest in which he's the good guy and Trump is the villain. He must present a compelling alternative vision of America and persuade voters he better for the economy, affordable healthcare, immigration, and foreign policy.
I think a lot of moderate and wealthy establishment Democrats would rather see Trump win because they like this economy rather than vote for Sanders. If he wins the nomination and loses I can't help thinking it's because these Democrats stayed home or went with Trump. It's about money and power not Democrats or making America better.