Wow, I'm impressed someone else had heard of that - SCUDs in Afghanistan have been forgotten. I only found out about it researching a paper I was writing on the Iran-Iraq War.
The Afghan government fired MORE SCUDs than anyone - including Iran and Iraq - have ever fired. If I recall correctly, they lobbed something like 1000+ SCUDs at the Mujahedin.
It's basically a terror weapon.
IIRC it was mentioned in “The Bear Trap” by some Pakistani ISI fellow