(The Google post referenced wasn't recent, but a good two years before the SEO Tip one.)
You quoted the wrong bit, and distorted what was said (probably unintentionally), which isn't all that different from what everyone keeps saying: Write for humans, and the rest will mostly take care of itself. The real point there is:
If you are able to entice users to click on your website in the Google SERPs, then they return later and search for a similar keyword, your website will be ranked higher!
Good description -> more clicks -> better ranking (Slightly. In some cases.)
What's actually important in that process is people being made to click. The meta description isn't inherently helping the rank by simply existing, the way that an h1 tag is inherently important.
It's worth also noting that this is not a justification for tricking people into clicking with misleading descriptions, either. People will notice, and back out to the results to try something else. When Google notices this behavior, they actually offer to the block the offending site altogether(the assumption being that you immediately bounce back because the information was bad, false, etc.) which is obviously not what you're after. While the feature's announcement does say this wasn't currently being used as a signal for negative ranking, the option is left open, and would be a reasonable end result.