Coffee houses are noisy, and require amplification. Although many UK folk clubs do have this, traditionally they are unamplified, and require both the audience to listen, and the singer to project.
I have sung in pubs and cafés, and I don't like doing it. I prefer to try to encourage people listen to what I'm singing by vocal dexterity, not force them to, by electronic overpowerment.
Microphones etc have their place, but that place is to enable people to hear, when they WANT to listen.