Mr. ginto confessed Belle he did not bring magic back for revenge. Why do you think he did it then?

To find his son.

I think to balance out the power for his own gain.... While he is marvellously sarcastic and we all pag-ibig him, he does pag-ibig to be in control or at least in a position where he can seize control. And the magic may help him find his son which is another reason I think he did it....