Are you allowed to talk on the phone in the bathroom?

R' OY (in Shas's newspaper) stated that a person should not talk on the phone in the bathroom unless it is very urgent (loss of money or sickness). He said that the reason is only for tznius. He quotes the ספר חרדים: "אין משיחין בבית הכסא מפני סכנת שדים המצויים שם, וצריך צניעות ושתיקה להינצל מהם". He points out that the nowadays in our bathrooms since we have running water and they are clean there is no סכנת שדים and it is only a din in tznius.