In theory if they are using FileVault they don’t have to do that, a simple reformat will lose the keys…or telling “Find My Mac” the thing has been lost and to obliterate the wrapped keys would do it.
In practice if you watch what the NSA does with hard disks and SSDs before recycling computers they are a bit more conservative. “The device is to be turned over for recycling or donation only after the disk drive or SSD has been transformed into a liquid state and then back to solid”
