I agree. Without these people the site could fall into a mess of bad answers or a self promotion answer driven platform like Quora.
And the more points you have, the upper you stay in the ranks and you can always embed their badge in your website.
So, yes, they don't earn money, but they receive visibility
SO also has a jobs site, which I suppose can be linked to your profile if you want it to.
A company I consulted at one time was trying to improve it's profile for job applicants so they wanted people to put up their github profiles and SO profiles in some advertisements or whatever they were doing - I think it was on linkedIn they were doing this. Anyway I think they stopped because nobody had a particularly high impressive number so why would you even want to do that (but they did it)
Given both that suspicion, and how they seem to behave about prominent github profiles and such, I think that being in the top 20th percentile or so on SO and a strong focus on the tags that correlate to the terms in a job announcement might be a big draw to some HR people/managers who just really don't want to mess up one more time! After the fifth complaint or so of programmers we hire don't know how to code or whatever - it might be soothing.
I think some sympathy is due for the working-for-free workers on stack exchange, at least from us, Hacker News' unpaid content authors.
In return they get points.
Points allow for showing how important they are to the community.
Points that have zero cash value.
Disgruntled volunteers are not going to be easy to replace.
This probably won't continue to feel satisfying if SE doesn't show respect for its volunteers. The force multiplier only exists because the moderators keep the site clean and well-organized. It sounds like SE both explicitly and implicitly showed gratitude for this effort, but now they are failing to do so.
if you want to start assigning a dollar value to subjective experiences like that, the argument goes both ways. you should pay more to people who experience more emotional distress from their jobs. but in that case a majority of companies would probably go bankrupt, since most people despise their jobs.