Nick from DigitalOcean here; yes! It's in the bottom of the blog post
>>> Our engineering team is working hard to bring you even more functionality for your databases in 2019. We plan to have additional engines such as Redis and MySQL, private networking with enhanced VPC, metrics, and alerting through Insights.
As a pretty basic user, it is mostly about adaptation costs regarding tooling, infra and code. My current stack mostly includes mysql as the default db, so my applications and tools also default to mysql and for now I don't see a huge benefit since all I mainly do is CRUD. I am considering pgsql for some new stuff, but for the existing applications I don't see any benefit to move to postgre for now.