I think you're missing the point. It's not about value, it's about means. $8/month could mean a lot or mean very little to your finances. That doesn't mean the person that can afford it is any more valuable to the conversation.
But the people who would pay $8 dollars, regardless of finances, derive enough value from being bluechecked in the first place. Paying the money would fulfill would fulfill a higher rung of their hierarchy of needs than it would for most others.
