Just my 2 cents:
It can't hurt to defragment, unless you count time loss. Depending on drive size, it can take a lot of time. I know some versions of Windows will inform you if defragmenting is not needed.
To speed things up, it is good to disable any applications and such that will interrupt the scan or it will start over! You may want to reboot in Safe Mode to do it.
Those articles probably say something similar, but better.