When one receives a bowl and thinks about the use it will give it, surely the most immediate thing that comes to populate their imagination is the function of containing food. And perhaps, just if it wasn't appropriate for this usage, I would then think of third options like containing other types of objects. The proof that most strongly and symbolically supports this hypothesis is found in the teachings of the person who probably thought the ultimate meaning of a bowl the most: the cynic Diogenes of Sinope.
This famous philosopher spent his days dedicated to getting rid of the material, for being superfluous and a mere tether or obstacle on the ascetic path towards wisdom. It is said of him that he barely had a jar at home plus a cloak to cover himself with, a staff to help him walk and a bag, where he carried a small vessel and a bowl to eat as his only possessions. According to his cosmology, he did not need more, and at the same time he could not afford to have fewer things to lead a functional life that served his wisdom purpose. But one day, seeing a child eat his lentils directly contained in the concavity of a type of mushroom-shaped Greek bread, he already considered the bowl completely dispensable. Because, ultimately, for this illustrious thinker, the essence of this useful conquiform is receiving food inside.