In so far as I can tell the point of having a creed is not for internal use. It is the shorthand that you foist off on strangers so they can get an idea of what your community is all about. And the point of mentioning that you go to church to gain the moral credibility you get from your church. More specifically from them having not thrown you out.
I think this one of the major reasons that atheists are so mistrusted. It's a comparative judgement against church goers. A church goer is tacitly approved of and vetted by their congregation. Someone with no affiliation at all can only be trusted on their own credentials. Credentials that they are unlikely to have and even then, there is no shorthand. So if you have a creed and a congregation it is a short hand to credibility.
You have the tacit approval of your congregation and they have the assumed allegiance to a mission statement short enough to look up. Without those things a person is an unknown quantity who's morals are grounded in either "nothing" or some idiosyncratic philosophical justification. And that justification takes too much time and sophistication to evaluate, so one gets no credibility from it even if its better than most creeds.
"Good without God" misses the totally legitimate game theory analysis that "Good without community" is an uncheckable assertion. Being outside of a faith group gives you the same moral appearance that being without a degree gives an intellectual appearance. Without a vetting organization no one is going to take you seriously until your personal reputation is spectacular.
All of this is to say that I think even the atheists among us should reconsider what not going to church means intersocially and why belonging to a group with a creed might not be the moral subjugation that some folks imagine it to be.