There are accessibility reasons why you’d want a mic, especially with churches dominated by older people who are more likely to have hearing problems. But I loved the setup one of my old churches had. There was a room in the back behind windows that had a speaker on the ceiling. There was a single knob that turned it up and down and there was a little radio transmitter with ear piece receivers if anybody wanted that. And then there was a 4 channel mixer up front that plugged into the feed to the back. So for most of the congregation, they’d sit up front and hear everything acoustically. In the back, they’d hear it mostly over the speaker and someone would just sit there and turn the knob up and down as needed. Was it ideal? No. But it was a setup that worked for 30 years straight with only one or two points of failure which rarely failed and were relatively cheap and easy to repair.