I happen to enjoy both scenarios, large pop and low pop, but for the sake of this quote, low pop gives a server a small town feel. The community is small enough to where you can have a pretty friendly and daily relationship with most players. I also find that it makes the money-making aspect a bit safer with only 1-3 outlaws on the server, so having that feeling of security encourages me to be that salt/iron miner or cow rancher or food maker or what have you without needing a large (Or any) security force.