Mm no, we're actually telling you NOT to spam 15 posts, you get credits from simply replying, people have questions, you answer them, you start topics, you act as a member of the community instead of just grabbing free shit and leaving.
The entire point is that this is a forum and this community and for you to be allowed to take something out of it you have to put something in.
Which I mean, I think a lot of people here would do it voluntarily and don't care about credits, hence why there are people with 1000+ credits. Also, 'not a good idea' obviously it's a great idea, this forum has a ton of active users and makes a good deal of money.