It's just easier.
You don't have to worry about IT forgetting to wipe a drive or something.
You have a policy that says we take the SSD out before sending it to the reseller/donating.
A used SSD is a bad idea anyway, everything else on a laptop can more or less work indefinitely
From reliability perspective an used SSD is not a bad idea. Average SSD that has seen typical business / home use will become obsolete long before it reaches its TBW rating, and many drives last way beyond that. Keyboard, screen or even the motherboard are more likely to give up before the SSD.