If people see the Taliban use it (and let's face it, that's inevitable if the common people start using it) it will give bitcoin a bad name that we can't really recover from as long as it's used there.
Let's face the fact, what goes on in Afghanistan isn't a democracy. You only talk about the "Common People" and their feelings in perspective when it's a democracy as citizens get to air their divergent views, be heard and addressed. But in a dictatorship like we're going to experience soon in Afghanistan, the commoners don't have a say. Again, from the look of things, Bitcoin won't even be considered in the country since it's purely an Islamic state now. Muslims don't really welcome the Bitcoin idea as most of them think buying and owning Bitcoin/Cryptocurrencies is akin to gambling. Just the same way Muslims also frowns at interest based loans.