Goddess Vaishnavi is not only related to Lord Vishnu's energy…
SHE IS LORD VISHNU’S ENERGY.
In fact, She’s nothing but Lord Vishnu Himself.
In the Devi Bhagavatam, Lord Narayana tells Narada Muni that they are just the same one Divinity in two forms:
“The Paramātmā by His Yoga (i.e., Māyā Śakti, the Holy Ghost) divided Himself into two parts; the right side of which was male and the left side was the female Prakṛti.” - Devi Bhagavatam 9.1.10
“The Lord, who is All Will, willed and divided Himself into two parts, His Left part becoming female and His Right part becoming male. Then that Eternal One, Who is greatly loving, looked at the female, His left part, the Sole Receptacle to hold all the contents of love, very lovely to the eyes, and looking like the beautiful lotus. The loins of this woman defy the Moon; Her thighs put the plaintain trees quite in the background; Her breasts are mistaken for the beautiful Bel fruits; flowers are scattered as Her Hairs on the head; Her middle part is very slender, very beautiful to behold! Exceedingly lovely; appearance very calm; sweet smile reigning in Her lips; side long glances with Her; Her clothing is purified with fire; all over Her body decorated with gems. Her eyes, also, like the Chakora bird (Greek partridge) began to drink incessantly with joy the moon beams from the face of Śrī Kṛṣṇa, defying, as it were, the ten millions of moons.” - Devi Bhagvatam 9.2.27–34
True Vaishnavas are interested in Her to attain the Lord.
Sri and Madhva Vaishnavas devote themselves to Goddess Lakshmi to obtain Lord Narayana.
Ramanandi Vaishnavas devote themselves to Goddess Sita to obtain Lord Rama.
Krishnavite Vaishnavas devote themselves to Goddess Radha to obtain Lord Krishna.
In a metaphysical sense, the Goddess represents prakriti - material nature.
Vaishnavas use prakriti to learn and transcend - like a ladder.
In the Srimad Bhagavatam, Lord Krishna describes an ascetic who used material nature to learn about reality to Uddhava:
pṛthivī vāyur ākāśam
āpo ’gniś candramā raviḥ
kapoto ’jagaraḥ sindhuḥ
pataṅgo madhukṛd gajaḥmadhu-hā hariṇo mīnaḥ
piṅgalā kuraro ’rbhakaḥ
kumārī śara-kṛt sarpa
ūrṇanābhiḥ supeśakṛtete me guravo rājan
catur-viṁśatir āśritāḥ
śikṣā vṛttibhir eteṣām
anvaśikṣam ihātmanaḥTranslation:
“O King, I have taken shelter of twenty-four gurus, who are the following: the earth, air, sky, water, fire, moon, sun, pigeon and python; the sea, moth, honeybee, elephant and honey thief; the deer, the fish, the prostitute Piṅgalā, the kurara bird and the child; and the young girl, arrow maker, serpent, spider and wasp. My dear King, by studying their activities I have learned the science of the self.” - Srimad Bhagavatam 11.7.33-35
Goddess Vaishnavi is the Supreme Divine Mother, the Guide, the Guru, and the most merciful for Vaishnavas.