Seems like a waste of time, energy and mass to me..........
IF there is indeed a God then I suspect we are not alone in His creation..........
“...what was His purpose in creating a universe filled with trillions of other galaxies, trillions of light years away from our own if his only intent was to create life on our own planet?”
An intriguing question, for sure. I suggest a few possibilities.
1. To demonstrate the infinitude of his power, wisdom, and wonder.
2. To instill in us an appreciation for his love for us (when we contrast the enormity of creation with our own size. “What is man, that you are mindful of him?”)
3. To be explored and inhabited by mankind- either as an original “purpose” (had man not fallen), or in the future state when he restores creation.
Freegards!
Or its one of the greatest acts of Love.