Gray (2016) cautioned that “even when designers believed in the value of personas, they did not use this perspective in their visible design processes. What this might suggest is some disjuncture between reported use of methods and the actual design activity” (p. 4045)
In his video presentation, Dr. Schmidt referred to tendency as "UX Theater," where users go the process of UX but without applying what is learned to the design of the product. I imagine that until this process becomes second nature, you would have to put in as much effort at applying and integrating the persona as you do actually creating it.