Board Thread:General Discussion/@comment-26873003-20150830214630/@comment-1739368-20150831170340

Iirc, pretty sure the Devil's Palms unlock permanent stand abilities ( assuming you arnt born with them), while the holding corpse parts is only temporary. I think in Johnny and Valentine's case both were affected by the Palms, where as Gyro and Diego only had possession of a corpse part. The only reason Diego kept his is because the stand ability never actually came from the corpse, it was ferdinand's.