A lot of "pro" in this thread it seems.
Social does help in rankings, but not every social is equal.
The social signals that you buy from your fellow reseller - they usually are unnecessary.
But the social signals from aged accounts, like shoutouts from authority people, the ones that get re-shared and re-posted around social media - those are doing amazing job.
Its not easy to fake natural social signals and Google made few acquisitions to make sure it can read them properly.
Would I buy social signals from reseller anyways? Sure, they are cheap enough, but I wouldn't count it would help in rankings alone. I would use it more for indexing.