People who are new to the idea of user experience or the user-centered design process are often surprised when UX specialists want to test designs and prototypes before engineering writes code. They might assume UX handles A/B testing after release. Misunderstandings like this cause companies to exclude UX testing as a waste of time and budget.
An increasing number of case studies online show teams who adhere to the UX process and include rounds of user testing before delivering to engineering work more efficiently and get better products to market more quickly.
https://www.cmswire.com/digital-experience/user-testing-belongs-in-the-ux-process-heres-why/