God is possible -> God necessarily exists.
Means if it's possible God doesn't exist, then God is impossible. I understand that.
But if we say God is not an impossible thing for sure, then the argument states God exists.
I think God being possible is obvious, while God possibly not existing is not obvious. Therefore this argument is still good argument, if you accept that God being possible is obvious, while God possibly not existing is not obvious (it maybe he is a necessary existence).

