It's security marketing, in particular: they're trying to increase engagement with their bug bounty program. A big problem bug bounty programs that run without promotion run into is that the median submission is of terrible quality, but the best submissions are so good it's hard to get them through any other vector.

If you're looking to run a bug bounty for a specific feature and want to maximize quality while minimizing effort triaging terrible submissions, I think there are much more cost-effective ways to accomplish that by structuring the bounty program (for instance: I might not run it on a platform like Hackeroni at all).

But if you're looking to run bounties for all your stuff in the future and want to maximize the likelihood that the good bounty hunters will pay attention to you to begin with, this might be a pretty cost effective way to do that.