The main reason why it is a good decision by the Israeli parliament to ban UNRWA operating on all its territory is that like the Quatari emissary bringing US dollars to the Gaza Strip ¹, UNRWA paid its Gazan employees in US dollars.²

Like the Gaza-ISIS public service employees paid in US dollars provided by Quatar, those UNRWA employees were obligated to change their salary into Israeli shekels (the main currency in Gaza) with local money-changers who gave a cut to the Gaza-ISIS. Thus UNRWA's payments in US dollars helped the Gaza-ISIS receive funds in the right currency to purchase weaponry and construction materials for the tunnel system on the international market.

Banning UNRWA from operating on Israeli soil means that no longer can US dollars that enter Gaza via the salary of Gaza-ISIS-affiliated UNRWA employees re-finance the Gaza-ISIS. And that is a necessary move to prevent the Gaza-ISIS from re-emerging.

¹ https://edition.cnn.com/2023/12/11/middleeast/qatar-hamas-funds-israel-backing-intl/index.html

² https://www.nbcnewyork.com/news/national-international/israelis-lawsuit-says-un-agency-helps-hamas-by-paying-gaza-staff-in-dollars/5540250/