It is basic human decency to be nice and supportive (to an extent) of those that oppose you and have opposing views. It's even taught in the Bible to do good even to your enemy. It may not have been the best thing for his political campaign, but it showed more of his character.
Senator Sanders still intends to see this primary election through, and has yet to support Hillary Clinton. However, I believe that Senator Sanders will choose to support Hillary Clinton unless he sees that there is another candidate that he prefers. Unless such a candidate appears, I believe he will support Hillary Clinton.
Republicans are (as absolutely insanely ridiculous as it is) closing ranks around Drumph. We can't have a blowhard, morally bankrupt reality tv star hold this nation's highest office. It's essential that Democrats come together and face him as a united party. The Republicans are pretty much imploding, but they're still saying they're backing him. Sanders has a chance to keep contributing in the political spectrum, even if it's not as President.
Bernie is just as baas as the rest of them. Big promises and no delivery. He is renowned for never getting anything done. Seriously what has the guy accomplished? Squat. He did the thing in supporting Clinton because that is what good little doggies do, they curl up at their master's feet.