1) The most important lesson that Della and Jim seem to learn at the end is that quantification of love is an effort in futility. The gifts they purchase for each other cannot reflect the love and care that they have for one another. Both go out of the way to buy something “just a little bit near to being worthy of” the recipient. They become the magi, the wisest, probably by learning that the apparently precious means with which they try to quantify love are worthless in comparison with their feelings.
2) Della sobs while Jim comforts her. This probably indicates that the writer unwittingly endorses the dominant discourse of social roles assigned to men and women. The roles are gendered. Reactions of Jim and Della to the revelation of the apparent uselessness of their gifts suggest that Jim is a more rational and matured individual than Della. While Della reacts with a hysterical cry, Jim takes it easy and remains calm at the pathetic discoveries on the Christmas eve.