Kids or adults with retained/returned primitive reflexes tend to have poor posture, balance, and coordination.
Working on exercises to improve posture, balance, and coordination can be helpful, but the results tend to only last as long as they continue to do the exercises.
Higher levels of brain function may also be achieved, but often only for as long as they continue to the exercises.
"... have positive results with children who have poor balance, postural control, and motor skills combined with little or no evidence of abnormal primitive reflex activity. This group tend to respond with improved balance and coordination as long as the program continues, but changes in balance and coordination do not necessarily cross over to affect higher cognitive skills (academic performance, for example) if primitive reflexes persist beneath. In cases where a cluster of primitive reflexes persist in the school‐aged child, for a physical program to be optimally effective, exercises should be aimed at the earliest developmental and postural level of reflex abnormality rather than trying to impose direct training on higher skills." Attention Balance and Coordination
It makes sense to to start and address areas that are abnormal such as retained or returned primitive reflexes that interfere with normal movement patterns.