Theory on Why Religion/Spirituality Still Matters to People Like Camus put it, we want answers in a silent universe.
So of course we seek to find those, often in religion, because like you pointed out it is accessible to everyone in a way that science/philosophical theory may not be (though the Internet has certainly changed the reality and prevalence of scientific understanding, Nagel names this renowned new faith in science scientism).
Religion is resultant of something in the human conciseness, seeking understanding. Those who created religion/theory wanted to answer some of these empty questions (that likely, will never have a definitive objective answer) and those who follow seek not only answers, but comfort, community, and a sense of purpose.
I personally abhor organized religion, I really have strong anti-religious sentiments and can't help but lose some respect for people who blindly follow or preach Christianity or Islam. To me, it is ridiculous and has no place in the twenty-first century, but what I have learned is that I wish I could blindly believe, it would have brought me great comfort and great peace...instead I have to struggle, quite often, in finding my own meaning to my life. When my grandmother died last year I wasn't quite sure what to do, or how to think or feel, I reached an existential crisis where suddenly I felt like everything was much more finite than I had been lead to believe.. It was a very dark time in my life, one where I wish I could have appealed to religion to help me. So of course I understand the function of religion, it's not only great for keeping people disciplined and working collaboratively, but it also provides the psychic crutch needed for many to survive terrible circumstances and situations, look at the people in the Middle Ages-all the violence and war and disease, life was short, most people died and lived in abysmal conditions, of course they wanted to appeal to a God. That is not to say that today life is 'easy' in comparison, far from it, but there are newer religions that people appeal to, like the capitalist idea of success; money = highest good, or scientism ect. Religion at is fundamental, ideological basis, is still there, just in different, obscure forms than say Christianity and Islam, which again, as someone who feels very anti-religious/anti-ideology meets roadblocks regarding deconstructing it.