There is one advantage to erasing it (note: do not use a security erase or overwrite what's there; that results in SSD wear):
Your old MacBook Pro almost certainly did not use TRIM on the SSD. That means the SSD would have been forced to use its own garbage collection, which over time will cause the SSD to become slower and slower at writing information, for various complicated reasons related to the peculiar way NAND flash records data. Erasing the drive will reset the garbage collect, returning the drive to its original speed.
