If it were placebo there would not be traits to begin with. Traits have an impact on game play. The problem with the high motor trait is that EA gives the trait to far too many players. This renders the impact of the trait null and void. Also, when M19 first came out there were many game play issues and turning off high motor helped to correct some of those issues. Since that time, the game has been patched several times and most of the issues have been fixed.
Many folks, myself included, are going back to using the traits. However, in my personal use I give the traits to fewer players than EA does.
All of the traits have an impact to the game play, some have more impact than others.