When you doubt miracles you still might believe in God, a distant God who exists as a theoretical possibility. But that sort of God--a distant God we struggle to believe in--doesn't really show up in day to day life. Day to day, the only agents in the drama are human beings. God is far away and doesn't really have much to do with daily life.
In short, our disenchantment, doubts and skepticism impairs our ability to experience God as relational. And without the experience of God as a lived relationship the spiritual life becomes abstract, intellectual and theoretical. And it's hard to maintain a vibrant Christian life if all you have are abstractions, ideas and theories.
Many disenchanted, doubting and skeptical Christians get this and have worked hard to rethink God's transcendence so that our doubts don't create deism. A lot of good work is being done by process theology folks on this front. Check out, for example, process theologian John Cobb's book Jesus' Abba: The God Who Has Not Failed. In his book Cobb recognizes how liberal theology, due to its disenchantment, robs us of relationship with God, and Cobb works to give these believers a way, via process theology, to recover relationship with Jesus' Abba by emphasizing God's immanence rather than transcendence.
And it's here where I find an interesting connection with miracles.
When I hear my enchanted Christian friends talk about their experiences of constant, tiny little miracles during the day I heard something close to what process theologians are talking about. That sounds wildly implausible because my friends who speak of constant, tiny little miracles most definitely believe in a transcendent God intervening in the world, the exact thing process theologians reject.
Yes, I'm aware that the metaphysics between these two groups, the process theologians and my enchanted friends telling stories of God changing red lights to green, are totally at odds. But what I find similar is the lived experience. Both groups experience God as ever-present in life, always working or calling us to the good.
Both reject a deistic experience in favor of a lived, relational experience with God. Both groups experience God as benevolently present and active.
In short, when it comes to miracle stories I think we get hung up too much on the metaphysics, finding this or that miracle story as either plausible or implausible. But if we shift to ponder the experiential aspect of miracle stories what we find is a relational experience, the experience of God being benevolently present in our daily lives. Theologically, I think you can get to that experience in different sorts ways, through transcendence or through immanence, but the final goal is the same.
A lived relationship with God.