The fact that Palestinian Arabs use the shekel as their currency means that Arabic terrorist media will regularly publish the exchange rates of the shekel against other world currencies.
This means that we have a situation where Islamic Jihad media closely follows the strength of the shekel against the dollar, euro, Egyptian pound and Jordanian dinar.
A strong shekel means that they can buy weapons for a better price.
The terrorists know quite well that if a Palestinian Arab currency would be created, as some urge, it would be a disaster. Staying with the Israeli currency is good business for terrorists.