Biblical wisdom mostly. Certain parts definitely don’t hold up to modern morality, but there is a lot well-thought-out advice buried in it that has helped people in Judeo-Christian areas for thousands of years.
One of the Proverbs in particular comes to mind: “He who walks with the wise grows wise, but a companion of fools suffers harm.” Hard to argue against the inherent wisdom in such a statement.
Also, like you, I have an appreciation for old churches and some religious art.
How does it feel to be on the same side as most preachers and weekly church-goers?
Few things drives them more nuts than people who call themselves Christians and don’t even attempt to be followers of Christ. Trying and failing is one thing, and always an embarrassment to the church, but living like the worst dregs of society, while using that name, is worse than an intentional smear campaign.