I would say ultimately the unethical practices used by past researchers were useful. Based off past research techniques used, we now have a code of ethics that defines what behaviors in research are acceptable and what behaviors are unethical. If there were never any unethical practices carried out, the code of ethics that we rely on today may be different or nonexistent.
While I do not condone the unethical acts, either then or now, I believe that they play a vital role in developing and updating what we see as good research versus unacceptable research practices. As practices are used, we are able to see the effects they have on research, and the subjects. When the outcomes are not acceptable based on societal constructs, or trust of the public, we understand the methods to be unethical. In 2017 Fisher, notes that the code of ethics continues to update based on not only on the experience and ideology of board psychologist but also based on the current political, social, and economic climate. As more research is conducted we are able to identify new unacceptable methods to add to the list.