While some have done so to fool people, gain fame, or even try and gain finacially.

The Church is very careful to screen people for psychiatric disorders and other medical problems when they claim something like the stigmata. In charity, the Church does not condemn these people, but recognizes that they have an illness, they may truly believe that the stigmata they bear is of God, and are not trying to fool others. This way when someone like Padre Pio is given the approbation of the Church, we can be assured that the case has been investigated, not only by the Church, but by physicans including non-catholics and non-believers, who attest there are no natural, medical, or psychiatric reasons for the phenomina.