You “need” faith because ultimate commitments (to theism, naturalism, moral realism, etc.) always outrun strictly demonstrative evidence, so trust/faith is unavoidable for everyone, believer or not. Faith is not invented to explain evil away, but is the stance of trusting God’s goodness while freely choosing the good in a world where evil really is possible and often devastating.
If God were to constantly intervene in human affairs and make everything 'right'...then, yes, there would be no need for faith. But what kind of world would that be?
A world without moral agency. A world without virtue.
What would be the purpose?
It is only through God's ultimate redemption of the world through Jesus Christ that any of this really makes sense. At least to the believer.
You seem to be saying that that faith is a gratuitous extra. Something that WE are creating to navigate the crookedness of life. Similar to the idea that we've created God to explain our place in the universe so that it isn't simply a cold, heartless accumulation of carbon based star stuff.
From a believer's perspective moral agency resulting in virtue...or not...is essential for the progress/learning of human beings. In the mix of it all...a fallen world...there is going to be a LOT of crookedness. The lion's share unredeemable in the here and now. That is where the belief/hope in Jesus Christ comes into the picture. That somehow the Atonement of Christ will make everything right.
That's a BIG ask, right?
My two cents.
Regards,
MG