With the advances in digital technology and small, high efficiency class "D" amps I would have thought someone would have come up with a different system to the "brute force" approach of a few, relatively high powered speakers? Especially for very difficult acoustic spaces such as churches.
A collection of very unobtrusive, "hi-fi" cabs with a built in 10W say,class D amp and a selectable delay unit could be used. The whole lot powered over the cable much as Po'ethernet?
Or, the cabs could pickup local juice and be linked via wireless or even a H' aid loop? IR remote setting of delay and wick?
Or am I just re-inventing the wheel? And a square one to boot!
Apart from the delay, which would indeed be an advantage, you're describing the small speakers on each pillar which I often used to see in churches. "Local juice" is rarely well-distributed in traditional church buildings though!