I didn't say that it was useless, but only of limited use.
Guerilla warfare is mostly about small, lightly armed groups trying to topple a government. Tanks are designed for supporting infantry, attacking each other, infantry, and artillery unites massed on the battlefield. In many cities, the streets are too narrow for tanks to even go.
Of course, tanks can help in urban guerilla warfare, but they hardly constitute a major step in fighting the terrorists. Only much better intelligence can bring about the downfall of the terrorists.