The difference is realizing the possibility of implementation. Clinton's plan is what Sanders would likely end up negotiating down to. Sanders sets likable goalposts, whereas Clinton sets realistic ones. Then again, neither plan would likely pass Congress considering who is in control there, so both are really moot points.
If both are moot points, why should a Democrat support Hillary over Bernie?
Clinton would probably be a better political negotiator. This wouldn't be the Clintons' first rodeo, and they might be able to work with congress more effectively than Sanders.
Also, there's of course electablity. Obviously, if Clinton's indicted she'd be even worse off in the general election than Sanders, but otherwise Clinton would probably fare better in a general election campaign than Sanders.
