As per the saints, Lord Krishna Bhakti too is Like the "Kalpvriksha" for his devotees. From the God, whatever, is asked for, God provides that to his devotee. God is so kind that he provides everything to his devotee even without being asked for. Surely, He does not give anything which shall be harmful to his devotee or anybody else. If you have firm faith in God & your wish is pure then God shall certainly fulfill that wish. Just like an unmarried woman, who when gets married to a man, automatically enjoys all the affluence of her husband; similarly when a devotee by his/her devotion gets to the God, then that devotee automatically gets all the affluence of God & of this world. This whole world is created by God only, so when one is able to get to the God, then that person too gets all the affluence of this world. As per "Srimad-Bhagwat", in the past, God became very happy with the devotion of child "Dhruva" & gave him all the boons & the kingdom of the world.
The essence is that, whatever you want, material or spiritual, you can get it from God by becoming His devotee. God Himself declares in "Bhagwat Gita":
"ananyas cintayanto mam
ye janah paryupasate
yoga-ksemam vahamy aham" (Bhagwat Gita: Chapter Nine verse 22)
"Sri Krishna said to Arjuna: But those who always worship Me with exclusive devotion, meditating on My transcendental form—to them I carry what they lack, and I preserve what they have."
"mam cha yo ’vyabhicharena
sa gunan samatityaitan
brahma-bhuyaya kalpate" (Bhagwat Gita: Chapter Fourteen verse 26)
"Sri Krishna said: O Arjuna, One who engages in full devotional service to Him, unfailing in all circumstances, at once transcends the modes of material nature and thus comes to the level of Brahman & attains God."
"man-mana bhava mad-bhakto
mad-yaji mam namaskuru
mam evaishyasi satyam te
pratijane priyo ’si me" (Bhagwat Gita: Chapter Eighteen verse 65)
"Sri Krishna said: O Arjuna, Always think of Me, become My devotee, worship Me and offer your homage unto Me. Thus you will come to Me without fail. I promise you this because you are My very dear friend."
mam ekam saranam vraja
aham tvam sarva-papebhyo
mokshayisyami ma suchah" (Bhagwat Gita: Chapter Eighteen verse 66)
"Sri Krishna said: O Arjuna, Abandon all varieties of religion and just surrender unto Me. I shall deliver you from all sinful reactions. Do not fear."
So as the God promises that He shall always protect His devotee & fulfill all his/her rightful desires, so let's always be with God & keep Him in our thoughts. Remember, Lord Krishna Bhakti is Like Boon Giving Tree Kalpvriksha.
Jai Sri Krishna