It's soluble, yes. It's "dreadfully toxic", even more than everything else in the darkroom.

It also forms an insoluble salt with sulfate ("baryte", used among other things for the coating of baryta papers, contrast substance in X-ray examinations, weight material in drilling fluids, filler in paints and other pigments), which makes it somewhat useless in any process involving sulfate, sulfite, thiosulfate and similar anions.

The question shouldn't be "is there any reason why you shouldn't", but rather "is there any conceivable reason why you should"?