It's actually completely unnecessary. Sweden has some of the best education in the world and it doesn't have standardized tests. You know why? Because they fit education to however someone wants to learn. You can pick a career and learn about that for most of your time in school.
All standardized tests do is expect everyone to reach the same level of intelligence when frankly not everyone can be the same.
Take a tree-climbing contest. You have a bear, a fish, and a horse. You tell them all you can how to climb that tree. But you have three vastly different individuals there, so only one of them, the bear, will be able to climb that tree.
Standardized tests only make it so you learn a linear type of education. All it does is expect everyone to learn the same thing. But that shouldn't be what education is about. Education should be fitted to deal with different types of people. One size does NOT fit all when it comes to standardized tests.
People in Northern Europe understand this. Places like America do not.