Confessionalism (NOT confessionalization, which is the process of codifying church confessions) broadly speaking is the practice of confessing what one believes (Latin credo "I believe") and practicing this confession in church life. Church historian Carl Trueman has written on the benefits of confessionalism (here and here). In the first part, Trueman deals with how the confession without discipline is no real confession at all. In the second part, Trueman deals with the issue of having discipline without confession, which results in "the stage ... [being] set for potential pastoral tyranny. I would like to reflect here with regards to the necessary of confessions for the discipline of the church.
In churches which focus more on emotions and de-emphasize doctrine, problems related to doctrinal teaching within the church will not surface. Such a church however is not functioning as one, and will easily go astray, as being officially not concerned about doctrine just means that that church will fall prey to every wind of doctrine that comes its way.
Where there is doctrinal concern, what will happen however when doctrines are being introduced into the church by those not part of its "core" leadership? For example, if someone comes in and strongly advocates for Young-earth Creationism, while the church leadership does not take a position on the issue, can the church leadership stop the person from doing so? Upon what basis can they tell anyone to not teach doctrine X, where X can refer to any doctrine under the sun? The answer is that biblically, if they do not take a stand on the issue, they have no basis to forbid anyone to teach doctrine X. If the church does not state that this position is unbiblical, they have no right to forbid its teaching. To do otherwise is pastoral tyranny which is sin that needs to be repented of.
The benefits of confessionalism is that it functions as a basis for managing the teaching of doctrine. Abiding by one's confession means that one has an objective standard to allow or disallow the teaching of diverse doctrines. Doctrines not condemned by creeds and confessions that the church subscribes to have to be tolerated within the church. The pastor could very well disagree with it, and speak against it, but he has no right to forbid it. For example, both supralapsarianism and infralapsarianism are to be tolerated in Reformed churches, since the Reformed confessions do not take a side on this issue. To censure an elder for teaching infralapsarianism when one is supralapsarian, or vice versa, is tyranny, for going beyond what the church considers as orthodoxy and imposing it on your Christian brother.
Confessionalism helps safeguard orthodoxy and safeguards what is considers necessary for the functioning of the church. To the extent that churches desire discipline within the church but is not confessional, to that extent the discipline process in the church is ripe for pastoral abuse and tyranny. Furthermore, since discipline does not pertain to doctrine only, churches that desire to practice discipline without being confessional are extremely susceptible to all manner of abuse by those in leadership not only in discipline of doctrine but also in discipline of the (moral) lives of their congregation, and in conflict resolutions and counseling too.