So, essentially, the performance test is pretty bogus as it doesn't test the actual SSD performance.
What we are seeing here is a test of Apple's "copy" function, which really just creates an alias pointer to the same file, which only applies when you are copying files within the same drive, the actual rewrite of the new file will occur when it is altered.
The proper SSD test would be to perform writes and reads from separate media, which would test the entire I/O subsystem. Copying the same files back and forth on the same drive is kind of a scam test.
Now, one issue with this is in the event of data reclamation. Having files copied to separate locations means that if an area on the SSD fries or becomes unusable, the ability to access an actual file copy allows recovery more likely. Here, if the actual file area gets corrupted, the base pointer and its new file alias will both point to the damaged file location--hence, loss of data. Also, by making actual copies, the index area is spread out, possibly to multiple tracks, allowing for easier access to a copied file. Now, some will say, that this is where backups come into play, but the exposure exists to lose files more readily when one is not physically copying files to multiple locations within the drive.