Two users with same amount of earned merit can have different quality and contributions on the forum. In addition, each user has favorite boards and can make very high quality posts in favorite boards but can make low quality posts in non-favorite boards. Because that user might not have knowledge and experience in non-favorite boards so that won't be able to contribute quality posts (correct in knowledge and helpful in practice). Fortunately, good posters won't spam even in their non-favorite boards.

There are some stories that can help for readers.
Inspirational stories from self-made promoted users