In merit system only member upto higher rank are able to give it but in thanks system all ranks are allowed to give it and the counter for this doesn't matter for our ranking unlike merit.
Seems like you still don't understand on how the merit system works. Even newbies can give merits to other members as long as they receive some to their posts, from other sources. This will give them sMerits that they can use to merit others.
Still, the "Thanks Button" is a pretty idea. It is nice to know that you are being appreciated every now and then.