So, like the previous poster said, the Harrier and/or VSTOL wasn't the only option available...
Why were the F15s and F16s based in Bagram at the time?
Why were the only strike platforms flown out of Kandahar the USMC Harrier and then the UK Harrier?
Why did they wait to put in cables?
Probably because the runway had large chunks missing out of it and was being repaired one half at a time. The Harrier was the only realistic option along with the A10.