A standard procedure helps the security check at the airport and board flights efficiently. It serves the airport system to move a large number of people.
Surgeons go through extensive standardized testing and licensing requirements to practice. The standard is to protect patients since no one is willing to risk their lives to have someone unlicensed operate on them.
However, it's essential to understand what schools use standardized tests to measure. The tests used to measure students' studying ability have little to do with learning. The biggest challenge in our public school system is to solve the conflicts between standardized testing (meeting its requirements in the curriculum) and addressing diverse student learning needs, pace, and styles (there is nothing standard about this).
The standardized or personalized only becomes a question when we are confused about who we are serving and what we are working to change.