The proof that a student has mastered a subject or skill can be demonstrated in different ways. All students select the “easiest” way but that is different for every person.
This is an example of a more traditional style of assessment. A research paper or worksheet allows students to report on their findings. This link opens to a pdf review of a video game.
Project based learning allows students to demonstrate learning by producing a product. This physical manifestation of knowledge is often something that student remember for life. The feelings of a success or a failure help cement learning.