Whenever I read Affinity's posts, I feel angry...
But going back for a moment- to Dracula using a hellfire whip-
It isnt all that strange. Consider that when he was Gabriel Belmont, member of the Brotherhood of Light, he used the Combat Cross, a whip weapon. He was an expert in whip combat.
He destroyed the holy Combat Cross which could be used against him and stood for God and the Brotherhood, both of whom he feels have betrayed him and caused his situation, but he is still accustomed to fighting with a whip, so it makes sense that he would still use a whip like weapon, only this time, an ethereal whip made from his own demonic powers.