Indeed this is a
selling ploy. The amount of silver needed to
mint those coins would be staggering, far more than the temple could hold. Most of the spoils from the temple went to pay for the restoration of
Rome after the recent Civil War, the building of the
Flavian Amphitheater, and Vespasian's Temple of
Peace. The more valuable objects from the Jerusalem Temple went on display in the Temple of
Peace after being paraded through the streets in 71 AD during
Vespasian and Titus' joint triumph celebrating the
Jewish War
victory. The silver vestments on display during the parade could hardly have been melted down and minted for
Judaea Capta denarii a full year before!
For further reading see: Flavius Josephus &
Flavian Rome - Edmondson, Mason, & Rives, and God's Gold: A quest for the Lost Temple Treasures of Jerusalem by Sean Kingsley