The Heart Sutra does not give a lot of context, but the Diamond Sutra certainly explains why it should be studied.
Subhūti, if the mind of a bodhisattva dwells in dharmas when practicing giving, then this is like a person in darkness who is unable to see anything. However, if the mind of a bodhisattva does not dwell in dharmas when practicing giving, then this is like a person who is able to see, for whom sunlight clearly illuminates the perception of various forms. Subhūti, in the next era, if there are good men or good women capable of accepting, maintaining, studying, and reciting this sūtra, then the Tathāgata by means of his buddha-wisdom is always aware of them and always sees them. These people all obtain immeasurable, limitless merit.
Subhūti, suppose there were a good man or a good woman who, in the morning, gave his or her body away as many times as there are grains of sand in the Ganges River. In the middle of the day, this person would also give his or her body away as many times as there are grains of sand in the Ganges River. Then in the evening, this person would also give his or her body away as many times as there are grains of sand in the Ganges River. Suppose this giving continued for incalculable billions of eons. If there are people again who hear this sūtra with a mind of belief, without doubt, then the merits of these people surpass the former merits. How much more so for those who write, accept, maintain, study, recite, and explain it?
Subhūti, to summarize, this sūtra has inconceivable, immeasurable, limitless merit. The Tathāgata speaks it to send forth those in the Great Vehicle, to send forth those in the Supreme Vehicle. If there are people able to accept, maintain, study, recite, and explain this sūtra to others, then the Tathāgata is always aware of them and always sees them. Thusly, these people are carrying the Anuttarā Samyaksaṃbodhi of the Tathāgata.
Subhūti, if there are good men and good women in the next era who accept, maintain, study, and recite this sūtra, and I were to fully explain all the merits attained, the minds of those listening could go mad with confusion, full of doubt and disbelief. Subhūti, understand that just as the meaning of this sūtra is inconceivable, its rewards of karma are also inconceivable.
These are just a few examples. Notice that in the Diamond Sutra, the Buddha does not advocate merely chanting the text. He explicitly includes studying the text and explaining it to others. As stated in the text many times, the fruition of study and cultivation of the Diamond Sutra is the limitless and immeasurable merit of Anuttara Samyaksambodhi (complete enlightenment and buddhahood). Never does it characterize the benefits of the sutra as fundamentally beyond the capabilities of any reader or listener. On the contrary, it states often that even repeating four lines from the sutra bestows vast merits.
In one part, though, the Diamond Sutra does state that some people will not benefit from it. These are the people who have rejected the Diamond Sutra in favor of "lesser teachings." In the Diamond Sutra, the Buddha states that they do this because they are clinging to notions of a self, a person, a being, and a life.