The South Africa striker again had to make-do with a substitute appearance in defeat at Manchester United yesterday.
"Benni isn't a lead-the-line man, so Dunny has taken his place," said Allardyce.
"Do I take Dunny out and put Benni in? The answer to that is 'no' because, particularly at home, Dunny's the best creative player, and the best goalscorer, we have at the moment.
"I didn't expect it to be like that at the start of the season, but Dunny has dropped into that position and he's been outstanding for us."
Allardyce added: "But when he gets the chance, he'll have to make sure he takes it and keeps it. Then, if we have to move Dunny somewhere else, we'll have to consider that."