Getting merit just because an artwork is incredibly done is not an issue. In fact, they deserved to be recognized and praised by others who were blown away by their work, especially for an artwork that required the integration of a brand and a roobet mascot. It's no problem
Looking back on the Bitcointalk 10th Anniversary contest, receiving a fuck ton of merit from various members isn't an issue, whether it's from solicitation or organic appreciation. Still, a well-received piece of art is preferable than a shallow and meaningless post that was created out of thin air.
Another thing is, merit is not guaranteed, you are at the mercy of the people who will give it to you and if they do end up giving some to you then you could do it but in the end it is totally up to guess if you will get anything or not. Same goes for roobet competition prizes as well but at least you know that you will be in contention, they will look at it and if you have confidence on your art work then you are going to win something if it is as good as you think. That is why I do not think that it is done for merit, but it is done to win something. I doubt that there is a single person who posted something to get merit without any belief they would win anything else.