When I'm scheduled to play at a mega church in my area, I'll play at 1 of like 6 satellite churches that have their own worship band. The main church streams the message to the satellite churches at a specified time, so all the bands have to finish at the same time. Most of the churches have a "Music Director" on a talkback mic... usually the keys player... to keep us in schedule. Since most of the musicians are paid musicians... it common to play with people you haven't played with before, so the MD is like a guide while we are playing playing. Since we have to finish at the sometime with all the other satellite churches, the MD will shorten/stretch or add a song... guiding the band, calling chords using the NNS... which is very common for most of the churches I play with that have an MD.
A talkback mic works well at the mega church I play with because all their satellite churches are sound treated well, zero backline or floor wedges... silent stage (all IEM's and drums fully caged), and a great sound system with paid sound engineer who knows how to mix. Our personal mix are in stereo... which we control on a mobile app (including the talkback mic)... and it sounds like a recording... until you hear the MD talking...