The answer to this question becomes more of an open-ended opinion-based discussion rather than one with a definitive & authoritative answer .
So brace up for a long answer.:))
As it is with the Sanātana Dharma aka Hinduism, there's no singular monolithic directive authority, since it being more of a loose conglomerate of various Schools of Thought and Sects (saṃpradāya). Thus the view and perspectives on whom or what to worship may change with place, time, the person you have considered as your "guide" and/or guru, etc.
The oldest of Vedic Texts aka the Rigveda says :-
Ekam sat viprā bahudhā vadanti
एकं सद्विप्रा बहुधा वदन्ति ।
i.e. The Truth is one, the wise express it in numerous ways.
[Rig Veda Samhita, 1.164.46].
There's a famous Subhāshitam (सुभाषितम् - a sanskrit aphorism or maxim),
which can also be found in several concluding parts of phal śrutis (फल श्रुति ) in Shri Vishnu Sahashranamam Stotram (श्रीविष्णुसहस्रनामस्तोत्रम् ).
ākāśāt patitaṃ toyaṃ yathā gacchati sāgaram |
sarvadevanamaskāraḥ keśavaṃ prati gacchati ||
आकाशात् पतितं तोयं यथा गच्छति सागरम् ।
सर्वदेवनमस्कारः केशवं प्रति गच्छति ॥
Meaning:- As all the raindrops falling from the sky ultimately meet their end in the ocean, the worship of any divine God ultimately reach the one Supreme Lord.
In Srimad Bhagvad Geeta [BG. 7.21], the God says:-
yo yo yāḿ yāḿ tanuḿ bhaktaḥ śraddhayārcitum icchati ।
tasya tasyācalāḿ śraddhāḿ tām eva vidadhāmy aham ॥
यो यो यां यां तनुं भक्तः श्रद्धयार्चितुमिच्छति।
तस्य तस्याचलां श्रद्धां तामेव विदधाम्यहम्।।
Meaning: Whatsoever form any devotee desires to worship with faith that (same) faith of his I make firm and unflinching.
Thus, in a way you’re basically worshipping the same “deity” in different forms.
(Obviously, there can be several other interpretations to all of the above verses leading to different perspectives and interpretations which itself innately leads to the heterogeneity within Hinduism ).
The parable of Blind men and an elephant, explains the above viewpoint of everything there is, as a manifestation of one Ultimate truth, quite effortlessly.
Now question is
I wonder if there are any benefits to this path of God realisation over worship of one single deity.
As interpreted above, since ultimately it's the same Supreme entity you're worshipping (through whatsoever method or to whosoever be it)
So, does it matter at the end which path was taken when the destination to be reached is indeed same.
Another interesting interpretation regarding the Significance of worshipping multiple deities which I have always heard from my elders and watched (in some form or another) is the "Analogy of a Nation".
If the Supreme Brahman - परब्रह्म, [ which might or might not get a Specific deity name (with some attributes or not - saguṇa or nirguṇa ) such as ādi Shakti or Para Shiva or Vishṇu/Nārayaṇa/Para Vāsudeva, etc - depending on the fundamental thelogical and philosophical views of the concerned sect ], is to be considered as the Head of the Nation then consider all the other deities (as per that particular sects' sectarian defined hierarchies) as working under the command of that Supreme Brahman - S.B. (who can be thought of as the Prime Minister in the Indian context)
As the PM distributes various portfolios to his different ministers, so does our S.B. , who have distributed all various departments of the universal existence to different Gods/ Demigods/ Deities, etc.
So, like if you want your Driving License to be made, you won't go the Prime Minister directly rather approach the local government administration officer.
Thus, if we want a particular desire of ours to be fulfilled we must pray to the deity in charge of.
For example: Remove Obstacles = Lord Gaṇesha, Wealth & Prosperity = Goddess Lakṣmī, Knowledge and Arts = Goddess Sarasvatī, etc.
On the contrary if you have direct connection with the P.M. chances of you being in an ever blissful and happy state, increases manifold and thus no requirement for pleasing any administrative officials.
I have always found this analogy silly in some form or other, but in some strange ways it seems to work (at-least for me).
Moreover, generally the Supreme God of any of the sects in hinduism are always the final goal to be attained or learned by the beleiver. So if that's your aim, then only one Supreme God need be worshipped perhaps.
Of the Four Puruṣārtha (पुरुषार्थ) - Dharma, Artha, Kama and Moksha (liberation, spiritual values), Moshka is generally considered as the final goal of our life to be attained (as per all school or sects), which in general, can only be provided by the Supreme Deity of the particular sect.
In that way, it seems more logical that you worship only the Supreme God (S.B.), in whatever form you might like or whatever school of thought or sects' ideas influence you the most.
Generally, the Smarta Tradition - (स्मार्त) , whose founder is generally attributed as the Adi Guru Shankaracharya, is considered as the blend of all the core philosophies of Hinduism and advocates for multiple deities worship in some form of other along with ones' own personal tutelary deity [इष्टदेवता, iṣṭa-deva] .
So, to conclude, depending on ones' material and/or spiritual desires and affinities one may choose their deities for worshipping.