By giving sMerits you are motivating users to continue making quality posts. More good quality posts = more content which are worth to read, this is what mostly of us want to see.
Finally, there are no reasons to hold your sMerits. What if everyone would have same attitude to not send their sMerits? Nobody will be able to rank up then
I agree. If you want to consider it a benefit, by giving sMerit to deserving posters, you are doing your part to encourage quality posts. If everyone uses the sMerit system properly, the good posters will rise up and the poor quality posts will diminish, which saves everyone time and makes for a better board.