Honor is a good reason to invade Afghanistan. It's also a good reason to invade Iraq.
But honor is misunderstood and greatly lacking in the postmodern world.
Afghanistan may not be good tank country. Though one advantage of a tank is you don't need roads and they can even make roads [with or without modifications]- and Afghanistan is a country that lacks roads.

As far as strategic value, there are few things to consider. First, India is the one of the next potential superpowers. And China is other. Afghanistan had been in a civil war for decades. We have some kind of war going on in Tibet. And more importantly, there is war between Pakistan and India which hasn't been resolved yet. Increasing the stablity of Afghanistan *should be* in the interests of China and India- and the stablity of China and India is definitely in US interests. India is probably more important to America than China. India will probably become more important to America than Europe is.
Iran is probably the bigger threat to world stablity than N Korea or even the entire continent of Africa. Afghanistan is of course between Iran, China, and India. It's the land route between China and middle east. And is a major producer of illegal drugs for Europe and of course supplier to the rest of the world.
Energy is the most important global issue, and oil is an important source of *cheap* energy. But terms of dollar spent, [illegal] drugs are a very significant issue. Illegal drugs are an aspect of organized crime and less organized crime:). Crime and organized crime are probably the biggest threat to world peace- and a major factor in terms of costs/liability to America and all other countries.