OSTM that in early religions, you worshipped because god was by no means benevolent, far from it. God was that scary mountain, or the sun/rain. Later on, god was a leader of tribes in battle and so forth. The lord thy god is a jealous god, and all that. So best to sacrifice animals, children, other precious stuff to placate the god. Just as you would offer a stronger tribe danegeld or other appeasement.
To be fair to christians, many would say that simple worship rather than gilded temples is the idea behind christianity- it marked the move to a personal worship, where thought and loyalty were enough and gold and oxen were not required. Though there is the odd abberation, like the precious ointment on the feet story- disciples saying, why pour ointment on his feet, you could have sold it, and given it to the poor. And jesus saying, you'll always have the poor, what about ME, good for her. (I paraphrase, but not much).
Expensive worship has always tended to be a mark of respect to the priest class as much as to the deity. Take the Bling Bishop, just suspended by the new Pope. He clearly felt that spending zillions on his comfort was to the greater glory etc. The new Pope equally clearly does not. And of course, in some cases, corruption and personal enrichment are common.
You still come back to- why does he need to be worshipped? Many would say, he deserves to be loved and that's all it is.
For me, I can't believe in any relationship with a god where that god would leave so many innocents to suffer, so it's a good example of why I think the idea of a personal relationship with a god is not a reality.