I'm constantly surprised more folks don't use FoundationDB, I'm pretty sure the Jepsen folks said something to the tune of the way FoundationDB is tested is far beyond what Jepsen does (Good talk on FDB testing: https://www.youtube.com/watch?v=4fFDFbi3toc).

My read is that most use cases just need something that works _enough_ at scale that the product doesn't fall over and any issues introduced by such bugs can be addressed manually (i.e. through customer support, or just sufficient ad-hoc error handling). Couple that with the investment some of these databases have put into onboarding and developer-acquisition, and you have something that can be quite compelling even compared to something which is fundamentally more correct.