That's a really good point, @stevescoins!
To expand on it a bit, you want both, but you need to lead with one or the other. Hopefully performance in one area will subsequently drive the other.
That said, I'd lead with monetary stability. The currency can exist on it's own, as many stable altcoins have little or no value beyond being currency. Content creation is just a USP that differentiates it from others.
With a stable currency, new investors can be attracted, which drives the value up, making post/curation rewards pay out more. In theory, that should attract (or reacquire) content creators, and the cycle continues.
If you build it, they will come.
I'd agree with you that monetary stability is more important to the altcoin's success.
I'm not sure ( and I recognize this is coming from a creator's bias) if that approach helps the social media platform component succeed.
We definitely need to create more demand for the altcoin by seeking businesses to accept it as currency. That would help both perspectives.