There's nothing called supernatural. Anything beyond natural is a lie. Therefore, ipso facto - not to be believed - of gods or devils alike.
Leaving out for the moment the impression gained from ancestors, the hereditary fears and drifts and trends -- the natural food of thought must be the impression made upon the brain by coming in contact, through the medium of the five senses, with what we call the outward world. The brain is natural. Its food is natural. The result -- thought -- must be natural. The supernatural can be constructed with no material except the natural. Of the supernatural, even assuming god(!) did some, we can have no conception.
God's miracles are supernatural acts that happen in the natural world. God's miracles provide us evidence that God exists. God is a supernatural person. With God being supernatural, God's Miracles are manifestations of God being supernatural. God's miracles in our lives manifest His glory and reinforce our faith.
Miracles, things that no humans being are capable of doing. The same came to Jesus by night, and said unto him, Rabbi, we know that thou art a teacher come from God: for no man can do these miracles that thou doest, except God be with him. (John 3:2 KJV)