Because they’re not obvious?
God is probably the least-obvious thing in the whole world. You can point to literally anything that you think is God, and someone can tell you, no that’s something else. Simply defining what God is is nigh-impossible.
I say this as a believer in God, although I’m not a Christian believer.
Obvious is the couch you’re sitting on. Obvious is the job you have to show up to. Obvious is the fact that your baby needs food.
Not obvious is whether God is responsible for a particular chain of events or not. Again, I say this as someone whose spent a lot of time thinking about how to attribute complex chains of events. Did God cause me to be born poor while I’m responsible for my six figure job? Or is it the other way around?