I believe it can absolutely be warm and inviting. I can see it with silver accents, it would be beautiful and very dramatic.

I think it would be very dark unless you have a lighter accent wall, but yes, I think it would look nice.

I painted my living room a grayish fern green last summer, and much as I loved it, by midafternoon in August I was having to turn lights on it was so dark--and this is a south facing house with a huge picture window. I painted the largest wall a light orange sherbet color, and it made all the difference in the world in warming up the room.