Well, for that the comparative features needs to be clearly laid out.

It solves a problem that others have not solved. Which problem is that? And how better does it work than whatever there was?

It's an analysis of a paper, not a feature checklist, so the article is for people who want to understand more about how FoundationDB works rather than trying to provide a "which system should I use" explanation.

Though "super reliable distributed database presenting a single logical shard to client code" is a class of system for which I don't think there's anything else even close out there, and I suspect generally if that's something you -need- then you'll already know that.

It's a highly scalable (as in powers iCloud services with billion users) distributed transactional KV store. It's owned by Apple and mostly developed by Apple and Snowflake.