Questions exist around the arts in the preaching of the gospel.  This question has arisen before in history.

Stained glass windows were “the bible of the poor” who could not read.  The symbols and colors spoke a message for the illiterate.  The message of the gospel was conveyed through art.

Similarly, halos conveyed a meaning of holiness or someone sent from God.  Again, images and colors mattered in the oil paintings.

So while we of the twenty-first century looking backward might think these things quaint or unnecessary, they did convey the gospel message to people who were not able to read the Bible for themselves.  This was a time of no TVs, no videos, no movies, no cell phones, no texts, no instant messaging, no technology.  All they had to work with to convey messages were stained glass windows, paintings, statues, songs and large Bibles recopied by hand by monks in monasteries that only a few could read.  They had to convey the message of the gospel in the mediums of the day.

Proverbs 22:28 Remove not the ancient landmark, which thy fathers have set.