Bhakti is not easy to obtain

Krishna will easily give bhuki (material opulence), mukti (liberation) or siddhi (mystic perfections) since it does not directly deal with Him. However, bhakti is personal and hence confidential and bhakti (by bhakti we mean pure bhakti and not mixed) attracts Krishna. Because bhakti is directly connected with Krishna and that Krishna is easily purchased by pure bhakti, to attain pure bhakti is not so easy as attaining mukti, or siddhi or bhukti.

However, by the mercy of a pure devotee, bhakti is attainable hence this path in line from Lord Chaitanya is the most unique and special since no other path or dharma or religion awards pure devotion. It is by the mercy of Lord Chaitanya and His direct followers we have access to bhakti which otherwise is a close and shut case (not accessible).

Srila Prabhupada says in Chapter 1 Nectar of Devotion  "Devotional service can in fact be attained only through the mercy of a pure devotee. In the Caitanya-caritāmṛta (Madhya 19.151) it is said, "By the mercy of the spiritual master who is a pure devotee and by the mercy of Kṛṣṇa one can achieve the platform of devotional service. There is no other way."

Hare Krishna