Or she knows she has little chance but is only running to discredit the investigations against her and the CF/ investigation into the DOJ investigation on server issue due to drop at some point.    As dislikable as she is, dems are so predjudiced against Trump they will vote for even her if it gets to a head to head.  It would not be the first time that a party felt they had to hold their nose while voting for a candidate.(Gore/Romney are recent examples)