I can't say I have high hopes given the odds of making first contact, but it'd still be a huge milestone for our civilization if we can survive it.
Would the effects be good? The truth can have bad effects, but so does not confronting reality.
Finding signals from aliens on some distant planet would be interesting for one news cycle. Then everything would continue on as before.
Plus, more fundamentally, I think most people intuitively find knowledge itself valuable. Even if bringing much joy to many people doesn’t erase mortgages, this dismissive attitude seems unjustified. Imo
The truly salient difference is that aliens unlike gods aren't focused around our loves but their own.
And I would argue that God is not ultimately focused just on us, but one of his interests is in helping us to get to know him since that is beneficial to us and he loves us. A big difference with an alien is that they would be a created being just like us (in Christian understanding). If they exist, we can't really presume to know whether they'd be just into their selfish interests, or perhaps know God and be committed to loving others the way God calls us to, etc.
That implication you mention is not present in the text at all, and if you think about what it says and what that means it paints a very different picture. I mean, the very process of creation is the shaping of a chaotic potential over a period of time that ends in a rest - that doesn't depict an all powerful god.
Specifically I'd suggest that you are uncritically repeating this perspective that lacks a basis in the text, and its justifications replaces persuasion with insistence and repetition . But it does not make sense and its sole reason for existing is to try and harmonize 'god is perfect' with the actual text.
Edit: To your second paragraph I'm uninterested in how a specific culture views the relationship between men and spirits, I'm referring to how they are human creations that are inherently anthropocentric - they are stories told by humans for humans to explain human things and so their stories are centered around human things.
So the difference between 'people that know other life exists because they believe in spiritual life', and 'people that know other life exists because they recorded a signal that was demonstrably extra terrestrial' is that the former group believes other life is centered on them/us and the latter group does not - I presume we'd ascribe to them similar internal life as to our own, but at the very least we wouldn't assume that their core purpose or sense of place would intersect with us in any way.
Genesis 2:4 et seq: The earth is already there in rough form. God finishes it and populates it with life.
A very powerful being, yes, but nothing requires omnipotence.
Job 38 seems to reflect more of an omnipotent God. But it's also much later than the Genesis creation accounts, by which time Hebrew culture had likely been exposed to Greek philosophical ideas about what properties God should have to be worthy of the title.