Danny put it excellently and if I could put it in context or give a reference I would love to attempt to make this even more clear and salient. Activity acts as a participation trophy for taking place in forum discussions while maintaining a bare minimum requirement not to spam and some other criteria. Merit acts as a trophy for a contribution deemed worthy by another member who has also contributed to the forum and now is able to pay it forward.
Asking or begging for merit would be like a fighter asking or begging for the title and belt without making their mark. This is like an actor looking for a nomination without playing a significant role.
This is a much broader mindset and it can be applied when looking at any endeavor, but you must be willing to be the fool. Be honest with your limited starting knowledge and do not be afraid to be the fool. Everybody starts somewhere and as long as you are operating on the same base principals and core foundation as the rest of us have agreed to then you are free to progress past being the fool with your own determination. Do not expect to earn merits, ever, rather hope to assist, contribute and inform others in a way that is meaningful and significant. Challenge yourself to learn more and be more, merits will soon become representative of what you have brought forward to the community. In my case, I believe I have been over-merited for my contribution so you might even find yourself lucky in that regard.
Since the merit has been implemented here in the forum is easier to detect which people are here with the only goal to earn some money, instead to give good contents to the forum. Nevertheless, I understand it can be somehow difficult to achieve a good position in order to get some paid activities.
I believe those begging for some merits are just newbies who don't understand how the forum works. They just want to get a bounty campaign with no effort at all.
It is sad to see how the forum has become, rather than a place where information is free for all, a place where a bunch of people wants to earn money at no cost, instead of people trying to give their best in order to get merits, rank up, and become important collaborators.
The merit system, at the first, didn't convince me at all, it remembers me the "likes" on the social media. Now, I fully understand why are they necessary, for, as you say, what the forum needs is meaningful and significant contributions.
Everyday we see desperate attempts, such the one we are answering right now, to get some merits. Maybe it is time to open a "merit contest" or something like that, in where the best publication wins some merits, and where everybody here can participate. Who knows, maybe it is useful for people to make their best for once, and a real opportunity to get some merits.