This chapter of 30 verses is about understanding the nature of the Supreme through knowing and meditation. However, v20-v23 besides breaking the continuity in the character of the discourse, advocate worship of gods for boon seeking that Krishna, as already seen, has chastised in Ch2, v42-v44. In order to appreciate that v20-v23 are interpolations, one my see how the original narrative runs, prior to their insertion, and subsequently thereafter.
Ch7, V14
If thee forsake well and true
To Me then thou come 'n grasp
Natures these Mine illusions.
daivī hyeṣhā guṇa-mayī mama māyā duratyayā
mām eva ye prapadyante māyām etāṁ taranti te
Ch7, V18
Noble as all worship Me
The knower true is selfsame Me.
udārāḥ sarva evaite jñānī tvātmaiva me matam
āsthitaḥ sa hi yuktātmā mām evānuttamāṁ gatim
Ch7, V19
Once in a while
Births after many,
Born who knows
I pervade worlds.
bahūnāṁ janmanām ante jñānavān māṁ prapadyate
vāsudevaḥ sarvam iti sa mahātmā su-durlabhaḥ
Then appear these inanities
V20
kāmais tais tair hṛita-jñānāḥ prapadyante 'nya-devatāḥ
taṁ taṁ niyamam āsthāya prakṛityā niyatāḥ svayā
Those whose knowledge has been carried away by material desires surrender to the celestial gods. Following their own nature, they worship the devatās, practicing rituals meant to propitiate these celestial personalities.
V21
yo yo yāṁ yāṁ tanuṁ bhaktaḥ śhraddhayārchitum ichchhati
tasya tasyāchalāṁ śhraddhāṁ tām eva vidadhāmyaham
Whatever celestial form a devotee seeks to worship with faith, I steady the faith of such a devotee in that form.
V22
sa tayā śhraddhayā yuktas tasyārādhanam īhate
labhate cha tataḥ kāmān mayaiva vihitān hi tān
Endowed with faith, the devotee worships a particular celestial god and obtains the
objects of desire. But in reality, I alone arrange these benefits.
V23
antavat tu phalaṁ teṣhāṁ tad bhavatyalpa-medhasām
devān deva-yajo yānti mad-bhaktā yānti mām api
But the fruit gained by these people of small understanding is perishable. Those who worship the celestial gods go to the celestial abodes, while my devotees come to me
Now back to good sense with
Ch7, V24
Unmanifest Am State Supreme
But saddle Me with form uncouth.
avyaktaṁ vyaktim āpannaṁ manyante mām abuddhayaḥ
paraṁ bhāvam ajānanto mamāvyayam anuttamam
Ch7, V25
Dull in delusion won't perceive
Me that's unborn veiled from them.
nāhaṁ prakāśhaḥ sarvasya yoga-māyā-samāvṛitaḥ
mūḍho 'yaṁ nābhijānāti loko mām ajam avyayam
Hence, undoubtedly v20 –v23 can be taken as inane interpolations.