Brahma ji, Vishnu ji, and Shiv ji are in birth and death
Durga ji is the mother of Brahma ji, Vishnu ji, and Shiv ji.
The great saints of Satyug considered Durga ji to be the Supreme God and they were so called "the knower of Vedas"
Brahma ji considers Vishnu ji to be the Supreme God and is astonished to see Vishnu ji meditating.
Vishnu ji Considers Durga to be the highest God.
Durga ji says that Brahm is the Supreme God and he lives in Brahmlok and he is the one to be worshipped.
In a nutshell neither Brahma ji and Vishnu ji, nor the saints of Satyug have the knowledge about Supreme God.
Moreover Durga ji considers Brahm to be the Supreme God who lives in Brahmlok whereas according to Gita Adhyay 8, Shlok 16, even Brahmlok is destructible, which means that even Brahm is not the Supreme God. This says for itself that, even Durga ji does not have the complete knowledge about the Supreme God.
What benefit would one derive by doing worship of Brahmaji, Vishnuji and Shivji when they themselves are not the Supreme God, do not know about the Supreme God, are in life and death and in effect are saying that Durga ji is complete God.
Secondly Durgaji is saying that one should worship Brahm which means to reap the full benefit one should worship the God above Durgaji
Now this Brahm in Gita ji Adhyay 18, Shlok 62, is asking Arjun to go in the refuge of Supreme God to attain supreme peace and eternal place (Satlok)
Hence, to achieve supreme peace and salvation one should worship the Complete God as told by Brahm in Gita ji and further elaborated in detail in Vedas by Brahm again.
That Supreme God is 'Kavir Dev' or in colloquial language 'Kabir Sahib'