Anhedral is there to counter the tendency to roll due to sideslip (Lv, Dihedral effect or Cnbeta depending on what Test Pilot School you went to!). This is important when one kicks off the drift in a crosswind landing. Wing Sweep is an important factor in increasing roll due to sideslip. So - if one doesn't or can't (due to control snags perhaps) easily keep wings level when the drift is eliminated and turned into beta, then best you reduce roll due to sideslip-{EG Anhedral on a Harrier}. Incidently the fact that this effect could not be properly overcome is the reason why the B52 gear swivelled to allow a landing in the "crab" and that one was told not to kick of drift in a Harrier crosswind nozzle or rolling vertical landing.