[jerf]

Simply filling the disk by any means runs the risk of your incriminating (or whatever) information being retained in a sector that got remapped out from under you that you can no longer write to.

Wiping the encryption key takes care of that problem, as well as being much faster.

[giancarlostoro]

Thank you, this is what I was trying to avoid doing by simply filling an SSD with random data. As you mention, I suppose FDE is better, but now you have to ask yourself whether OS level or hardware level is best. In this case if you override an encrypted partition with a fresh OS installation it wont matter as much since most of what will be left will be gibberish.

Sometimes I do just that, I'll install Linux encrypted, and then reinstall later without migrating any bytes. My main concern is work related / personal finance documents being left over on a laptop. I've tested plenty of forensic utilities on my system after erasing files.