Merit can play a part in this, but so can your activity - the number of posts and the amount of time you've spent posting. I'd say in general someone with thousands of posts is likely to be more trustworthy than a random new account with very low activity... so I don't think merit is the main factor here.
True, but we're unable to view others' post count until we view the profile. Only the Merit is displayed hence we tend to look at those first.
for me Merit is much important than activity and post counts because it is easy to become active but it is harder to gain merits .
but in all?they are all important and each member needs to have all to grow and ranked up.