I think its interesting to hear why people believe what they do, which doesn't really have much to do with religion, but more because im in general interested in belief and how people get to believe different things, what they believe etc. Because to me that is most of what defines us as humans. I will obviously argue against something if I disagree, but not with the purpose of trying to convince someone, but rather for them to clarify what they mean or believe, because it again tells something about how they got to believe it.
In other cases, I will argue against a belief if I think it is harmful.
I assume that you mean if its important to convince others? Because if its just to get my view across and opinion, then it is very important, as it would be difficult to communicate if they don't understand what im saying
But convincing others is only important in case I think their beliefs are harmful to themselves or others. Lets say a racist expressing their views, then it would be very important for me to convince them otherwise.
As I started by saying, a lot of my critique is meant to push or poke peoples beliefs on purpose if I disagree with them, or I don't feel like they have given a good reason for it, which is also automatically to try to understand their views. I hold the belief, that people should be able to defend whatever they believe in by giving a solid explanation for them.
What I mean by that is not that people shouldn't be able to believe something without having a solid proof, but if someone say that they believe in God, because they were raised to believe it. Then I don't think that is a good reason, as they clearly haven't thought about it then, if that makes sense.