I'm guessing the reason why is that the Jews migrated northwards from the Levantine / Africa / Spain upwards through Italy, Austria and then Germany, Poland, the Baltics.
Are there any Italian or Piedmontese / Venetian traces in Yiddish?
I know Jews used some Latins phrases in their languages. But it's too late for look up some sources...
A lot of words and expressions in the old Viennese dialect are Yiddish, though that dialect has all but disappeared from day to day interactions (you can find it in old movies and recordings).