NCAA members feel it is important to allow mementos or other awards to honor the hard work of student-athletes to achieve athletics success, from regular-season participation through a national championship.
To not allow this would mean national champions could not receive a ring, Heisman winners could not receive a trophy, or seniors could not receive a keepsake honoring years of hard work. Allowing these awards with reasonable limits is well within the confines of amateurism.
The limits are meant to level the playing field. NCAA members don’t want a large, profitable program or event to be able to provide more valuable gifts than less-profitable schools or events. The limits allow a reasonable award while helping to ensure that everybody participates on an equal footing.
For detailed information, see Bylaw 16.1 in the Division I manual.