Ask HN: Why is Facebook closing Moments?

I understand that Facebook have decided to shut down Moments: https://techcrunch.com/2019/01/24/facebook-is-shutting-down-moments-heres-how-to-save-all-your-photos/

I don't understand why they would choose to shutdown Moments (or a similar, under used service). Things that lead to my confusion:

* Facebook has insanely deep pockets * Facebook has likely automated all of the infrastructure and elasticity of the service (and, all of its services). I could see Facebook reaching a state where not a single person works on Moments, it's just a supported service on their infrastructure team, SRE style. * Facebook has masses of data, so it can't be an expensive service to maintain (especially, if people just upload the same photos to Facebook as that seems to be the obvious migration path) * Facebook would retain a non-critical app for it to experiment with features, let interns lose, allow users to drive feature requests and just see what Moments wants to become.

So, why bother to close it? Why not, just, keep it? What is the upside to shutting it down?