What happens if you expel the Jews?
From the wiki :
- Gains 5 time of yearly income in gold, -100 prestige, banish all Jewish courtiers
- Occasional -50 point technology events
- Removes negative opinion modifier from clergy
- Cancels any loan from Jews
- Gains Expelled Jews modifier : -2 diplomacy and -10% global tax modifier
- Gains Arbitrary if currently owns money from Jews
And obviously, you won't be able to borrow money from them anymore.