Nothing is keeping me from turning off fire spread. What happens is I can't light fires while that is on, so if I want to have a decorative fire, I have to turn on fire spread, light the fire, then turn it off. However, since I have a fire already lit on my property, if I want to light the second two fires, I could set my house on fire as I make the two new ones. I'd rather not have to finagle that every time I want a fire. Doing doFireTick false will allow the setting of fires, without the spread of them.
My thought was that since griefing isn't allowed, the server isn't a factions server, and we can set fire spread to false anyway, that maybe we could just set it for the map and not worry about it. But perhaps I'm missing a use for fire spread?