I can understand Israel not wanting to be without a local military rifle source. Perhaps they do not want to stake national existence on the good will of the US of A.
And the Tavor is shorter. I cannot say if it will be more reliable or more accurate at 450 meters or any of the other things that an army might want.
“There’s a rattle in my glove box,
A Federal twelve-gauge slug.” – Adam Carroll in song Porter Wagoner