I'm not sure how you differentiate what you received because of premium and what you would have got anyway. Having said that, you should cover your costs and a bit more as well as having the other features if you use them.

You're also more motivated to post more so there's that aspect that feeds in, and perhaps people are more compelled to engage as you're seen as more of a serious user (owner?) and contributor.

I don't think the financial rewards should be the main motivation as such, but the overall idea of what's being built and being a part of that (although you should of course be supported in return). Either way, hope it's fruitful for you!

And no pinning yet, but I think it's on the list.