Having heard Lucius' words, Kiana thought over them and found them to be reasonable. It wasn't just Lucius who wanted to keep his gift hidden. There were actually many other nobles and even commoners who kept their gifts hidden as well.
This could be due to a variety of reasons. Either they were doing it intentionally so that it would be keeping others in the blind, thus giving them the advantage, just the way Lucius was saying.
Or they did it because of shame. Sometimes, even when they got a high ranked gift, it could be something that was deemed to be useless or close to that. After all, even if one had a high ranked gift, it did not guarantee that it would be powerful.
That ranking merely showed the said gifts occurrence among the populace. It was just that the more powerful gifts were also rarer than the other kinds of gifts and thus having a higher rank was considered a sign of status.