I have a question concerning: Acts 19:19-20
"Also, many of those who had practiced magic brought their books together and burned them in the sight of all. And they counted up the value of them, and it totaled fifty thousand pieces of silver. So the word of the Lord grew mightily and prevailed."
I think I understand why the burning of the books of magic. But why count up the value and tell the value? Not sure I get that point? Would you please help me with this one?