Sig campaign is a joke and not worth your time. They pay very little. That's right I said it.
I don't necessarily disagree with you, because if you want to earn bitcoin or any other kind of compensation through employment of services, there are surely more lucrative kinds of work.
On the other hand, if you are already spending a considerable amount of time reading forum posts and contributing to various forum discussions through posts, then the extra payment can be a decent way to grow a person's BTC portfolio with some small amounts of BTC that did not cost any money (in essence helps in a small way to lower the dollar cost average of the total BTC holdings).