simple erase on Fusion drives equivalent to old secure erase?
I have an iMac with a 1TB Fusion drive. I'm going to sell it, so I wanted to securely erase the drive first. Not finding that option in Disk Utility in the recovery partition, I went to support chat. They told me that the current erase drive is functionally equivalent on the Fusion drives to a secure erase on a standard HD, ie, that recovery programs would not be able to retrieve any of my data from it.
Is that true? If not, is the best option to reinstall a clean OS, enable FileVault, and then again ease the drive before sale?