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 holding corpse parts is only temporary. I think in Johnny and Valentine's case both were affected by the Palms (or jesus?), where as Gyro and Diego only had possession of a corpse part. The only reason Diego kept his is because the eye of the saint gave him the ability to steal Ferdinand's stand ability, not Scary Monsters itself. And because it didn't originate from the corpse, he didn't lose it after losing possession of the eye.

It does seem like the super spin does unlock a stand as well though, or in johnny's case, another form. However, much like the corpse part method, the Stand is only temporary as you have to be on a horse to use it.