Questions about Krsna are loka-hitam

Source: SB 2.1.1

Śrī Śukadeva Gosvāmī said: My dear King, your question is glorious because it is very beneficial to all kinds of people. The answer to this question is the prime subject matter for hearing, and it is approved by all transcendentalists.

Questions of Parikshit maharaja are described as loka-hitam or beneficial to everyone because:

Lord Sri Chaitanya Mahaprabhu said that the highest perfection of life is to achieve the transcendental loving service of Krishna. Questions and Answers about Krishna elevate one to that transcendental position that is why they are glorified to be beneficial to all i.e. loka-hitam.
In Bhagavad Gita, it is said that simply by understanding the transcendental nature of Lord Krsna’s appearance, disappearance and activities one can immediately return home, back to Godhead, and never come back to this miserable condition of material existence. It is very auspicious, therefore, to hear always about Krsna. Maharaj Parikshit’s requested Sukadeva Goswami to speak about the activities of Krishna and hence it was beneficial to everyone – loka-hitam.
Activities of Krishna are non-different from Krishna Himself. As long as one is engaged in hearing such transcendental activities of Krishna, he remains aloof from the conditional life of material existence. Therefore, questions about the activities of Krishna are beneficial for everyone – loka-hitam.
Topics of Lord Krishna are so auspicious that they purify the speaker, the hearer and the inquirer. They are like the Ganges waters, which flow from Lord Krishna’s toe, and purify everyone wherever they go. Therefore questions about the Lord’s activities are beneficial for everyone – loka-hitam.