The last one will be your answer
It became faster and more reliable.
I believe that the direct effect of the passage of the Seventeenth Amendment is that it improved representation of the people, because now they were able to directly choose Senators, which made the whole voting process a lot democratic.
They did not try to stop it due, to already bad relations with the soviets, plus if you look at a map of divided Germany you can see that they were deep into the soviets territory. <span />