Still the cost benefit of getting second hand T72s over first hand BMP-2 is there. Afghans are very strapped for cash. So the cheaper the better.
As for transport - most inter district transport happens there over the Kabul - Gandhar - Herat - Mazar Sharif highways. (Actually the Government's writ runs only here) The main threat is from an ambush - triggered by IEDs. So neither BMP2 nor T72 is safe. Pilot recon and recon in force in advance is the only way. In fact this is what is implemented now.
For transport in pitched battles AFBs are useful. But Taliban prefers hit and run attacks. So a BMP2 won't have much of an effect.
Also to consider - the T72 chassis can be used in a number of ways. For example, the hull can be removed and replaced with a Flamethrower emplacement. BMPs cannot be customized.
Also the max armor of BMP2 is 33mm - that is vulnerable to 50mm Machineguns(recently captured from Americans!) The RPG inventory, though reduced can also be considered a major threat.
In the end the budget is the deciding factor.