If you want to increase your Rank at Hero or Legendary Member. You have more skills and knowledge about the cryptocurrency. If your post will be helpful and constructive then Higher Rank Member give you merits. Then your Rank will be increase.
Why should a higher-ranking user give merit to quality, constructive and informative posts.? You and low ranking members can also give Merit on useful posts as long as sMerit is still available.
You can also give Merit to users who rank higher if the post is considered quality, they also need Merit to get additional sMerit so that it can be distributed to other users. There is no need to hoard sMerit or save it because it will not give you any benefit.