Here is a key thing that I think that some people are misunderstanding about how Merit/sMerit works:

When you give sMerit, you do not lose any of your Merit.  Keeping sMerit does not increase your Merit balance and sending it does not decrease your Merit balance.

I have seen more than a few instances of people giving each other sMerit for good posts on a thread.  Probably, some of these were mutual sMeriting.  As in, "I'll send XXX a sMerit because they had a good post", followed by XXX, "I'll send YYY back a sMerit to thank them for sending me one".  So if you think about it in that way, you could potentially benefit from rewarding someone for a good post because they might thank you by returning the favor.

I see that there's been lots of complaints about the merit system but it's really a new change and I think it takes time to see how it works in practice for longer than just the initial deployment/adjustment period.