It depends on what your definition of success is. It probably gave insight in how organized the counter intelligence is and what their various response times ar

It depends on what your definition of success is. It probably gave insight in how organized the counter intelligence is and what their various response times are. The cost was low, especially given the possibility that the spy exchange that he took part in after a few months in jail might well have been planned long in advance. Military and intelligence organizations do this all the time, to constantly keep track of adversaries' response plans. They constantly change and have to be re-evalutated.