If content is actually valued in a way that is perceived as fair/valuable, that is a big deal. It means that the inflation being printed isn't just dumb dilution and there is genuine value being generated and rewarded appropriately. It means that others will seek to come in and participate in the exchange of value for whatever it is that they are creating on this platform. Others can come and participate in continuing to contribute to rewarding value, and be rewarded in the process (the motivation to buy-- influence within a fair system of value generation). A positive feedback loop.
And even if we aren't thinking along those lines, good content and engagement attracts users, and the platform's total networking power is what is valuable. If the system is perceived as fair then more people have reason to participate. Going the mass adoption route legitimizes the platform as a currency system in its own right.
I think there's a few holes in my argument / avenues for exploration here, but I can't quite figure it out right now.
RE: HF21: What Makes Steem Valuable?