I'll let you guys determine if this is a bug or not, but graves aren't flammable and they don't deteriorate. Perfect for fire prevention around a geothermal generator and the exterior wall of the colony.
Not sure if a bug, more like an exploit. I hope it will be fixed somehow, I am personally not going to use it because it feels like cheating though.
I agree. Maybe make it so that grass grows on the grave (possibly gives a debuff for unkempt grave), or make the grave gradually deteriorate.
It's like you are creating a firebreak, which is something people do in real life. Currently I normally just put a floor down to act as a firebreak, but I don't see an issue with doing that with graves.
Nothing wrong here. You can get the same effect for 2 metal by just building some concrete.