One of the main objectives of Physical Education in elementary schools is to encourage motivation so that the subject enhances academic performance and the practice of physical exercise. Didactic research should evaluate the effectiveness of educational methods to know if they are applicable, useful, and in what sense. Exergames are digital motor games that aim to stimulate players' motor skills. Gamification refers to the use of game-based elements in nongame contexts to motivate actions. This research evaluates a gamified exergaming intervention, designed to improve children's academic performance by focusing on understanding applicability and usefulness. A natural experiment was set up in schools according to a mixed methods design. The qualitative data herein reported were collected during a natural experiment with a nonrandomized controlled design. The qualitative research design was used with field notes, an open-questions questionnaire, individual semi-structured interviews and focus group interviews. Eight teachers and 417 students took part. A content analysis was chosen as the methodological orientation. The facilitators were the realism of their didactic design and their adaptability to different educational contexts. The main barriers were the required materials and facilities. Teachers and students' attitudes were very positive, although future use was inconclusive. These findings may imply that this study is one of the few to provide positive evidence for educational gamification. The "Mechanics-Dynamics-Aesthetics" gamification model and the "Just Dance Now" exergame may be applicable and useful for didactics in Physical Education, but all the participants' suggestions need to be considered to improve teaching interventions.