Biden had to do something to fill the time. Obama had no use for Biden. Not only is Biden goofy and demented, but apparently he was disruptive in meetings. So, Bammy shut him out of day to day affairs. Obama recognized Biden as the old White racist from a generation ago, that he truly is. Biden is so racist, racism is such a part of his life, he says incredibly racist things all the time and doesn't even realize it.
Obama kept Biden in a lock-box. Biden complained several times that he was not being included in Obama's Presidency. Can anyone imagine sending Biden overseas to attend a formal function? There is no way to predict what in the world he may say or do.
Biden was Obama's impeachment insurance, and nothing more. Other than that he was more than just useless, he was a detriment to Obama with constant gaffs and bizarre behavior which the White House and their media proxies had to constantly cover up.