When we talk about Christian beliefs, we are talking about Doctrine. Theology. Dogma. These are used to understand who God is, what Man is, how God works with us, and where we get our knowledge from. These are all, in the end, "knowing about." But if salvation were a matter of "knowing about," then we would be gnostics. Salvation by faith (one of our primary doctrines) is not salvation-by-understanding. Our ultimate goal is not to know about God, but "to know thee the only true God, and Jesus Christ whom thou hast sent" (John 17:3). Some people think that fretting over doctrine can be dispensed with: that it is desirable/possible to know God, separate from knowing about God.
So what is the value of studying our doctrine, and what the harm if we freely disagree over it? Well, consider again the metaphor/illustration I started with. Knowing God is in the balance. Those who keep their balance on that narrow pinnacle can do so only by fixing their gaze resolutely on God, who is, in this figure, at the true vertical position over that fixed point.
Now, if we were doing gymnastics or some other physical activity, knowing about the task to be done would be of obvious value. Studying film of ourselves on the balance beam, say, or learning from a coach who observes us closely, would inform our attempts to execute the maneuver we are called upon to do. It's not a substitute for doing the maneuver, but critiquing our performance makes doing the maneuver easier and better.
To know God is to know where the true vertical is. To know ourselves is to know all the imbalances of our bodies, which must be balanced in order to suspend ourselves from that true vertical. Christ is, in this figure, the very definition of true verticality. He is true God and true Man (one of the biggest dogmas there is!); in other words, I know God by knowing Christ and I know myself by knowing Christ. As I live out my life in communion with him, I know him-in-me and myself-in-him, too. And I study the Scriptures as well as pray in order to know about him better -- that I might know him better.
Someone who wants to argue over doctrinal formulae who isn't oneself trying to know God, or interested in helping you know God, is merely a fanatic. Someone trying to teach you how to know God without a sufficient knowledge of the doctrine and the value thereof, however, is a crackpot. Someone who denies the doctrine but says it's okay because love is what really matters, is a fraud. Beware all three sorts of guides. Meanwhile, someone trying to know God directly oneself, without the witness of the Church in all ages and places when that witness is freely available, is merely a fool.
We are not saved by correct doctrine, but we may be lost without it.