Why was it done...

     There will never be a satisfactory answer for the question. As many as there are different interest groups wanting answers just as many will be the plausibility of why and what and who (is) are involved with the formation of the universe and the reasons for CREATION.
From the spiritual consideration it is simple, one might say "..it was a supremely "capable" Entity who had tremendous powers we humans as yet are unaware of & do not yet possess" - they call him God.
& from that came many of the stories & teachings we all know and regard as Religions and Faiths.

This is not about denying the Creation of the Universe by God

This is a simple reason why:

 - HE WAS EXPRESSING AN EXUBERANCE OF EMOTIONS SO DIVINELY OVERPOWERING, ON AN IMMENSITY & MAGNITUDE HUMANS WILL NEVER BE ABLE TO UNDERSTAND -

   
    It can very primitively be likened to a human artist with an immense creative urge, producing a masterpiece with paint; only in HIS case it was a living, pulsing, kinetic finished end result. And with the 'creative' medium He used, the tremendous powers He only has - the finished "picture", the "expression", the "work" was Cosmic in grandeur, in scale, in its tremendous mind boggling complexity!! And it is vibrantly a LIVING CREATION.
 
    It could also very crudely be likened in a very limited way to  a huge whale leaping from the ocean out of sheer Joy - by itself an ordinary 'whale' event, just an expression of a whale emotion - however due to the immensity of the force which the creature commands the after effect is awesome - a huge spectacular splash like no other!


  Translate the force of the whale with the spectacular splash, & the beauty of the artist's masterpiece; & multiply those forces of 'expressions' with the supreme exuberance expressed by the Maker when He released His Joy - & due to His awesome powers - The Universe came into existence

 - A creative work so spectacularly perfect, so splendidly balanced & yet so  intricately complex,  unfathomable & infinite in its wonders.

    Humans study, analyze and attempt to unravel Creation. By so doing they imagine they would know the INTELLECT, understand the ENTITY which formed it.
    Many when they failed to gather any connection between the Universe and the Maker deny His existence and give many reasons and theories as to how it came about.
   
    Very simply if one studies an object say, a washing machine, eventually one would know rather a lot on the object being studied. BUT the person who made the machine, (or the factory from whence the object was formed) is not at all related to or in any way linked to the object, how then could any knowledge or understanding be gained about Him from studying the washing machine? 
Humans might derive that perhaps the maker of the washing machine likes cleanliness, or that he lives in a place where water is plenty,  or that he likes to clean in bulk, or that he enjoys seeing spinning wheels or listening to the sound of water gurgling. But other than such derivations, there is nothing in a million years of studying and tearing of the washing machine apart that is ever going to make anyone wiser about its engineer - who, what he is and the reason why he made what he made!
    Would it then be reasonable to conclude that the washing machine came into existence by a very complex juxtaposition of many unrelated factors which made conditions conducive to it being formed?

   Thus it is counterproductive & futile for any right thinking person to even attempt to understand the Maker of the Universe by studying His Handiwork - Nature and Creation.
Besides in this short life - THERE IS NO NEED TO DO THAT.
It is SUFFICIENTLY enriching if humans enjoy, explore & appreciate & learn about the INTELLIGENCE, BENEVOLENCE, & THE PERFECT PRECISE GENIUS which formed this Creation.
    And taking it up another step  .. humans need to know that after realizing the immense beauty and perfection He had brought into existence, He wanted to have us share in the wonderment.
 
And simply THAT IS OUR ROLE IN THIS LIFE -

'TO APPRECIATE WHILE WE LIVED OUT THE SHORT EARTHLY EXISTENCE WE HAVE BEEN GIVEN, THE WONDERS OF THE UNIVERSE AND MAKE THE MOST OF THE EXPERIENCE' 

The rest of other complicating rituals, faiths, sacraments, doctrines dictums, obligations  edicts do not factor in the equation of life.
And when one realizes that HE does not need or require an ounce of our worship or adoration it becomes even clearer the entire un-necessity of religion.