For many teams implementing microservices, these databases are a perfectly reasonable choice for many reasons:

1. Teams that are refactoring existing applications into microservices usually have experience with both SQL and object-relational mapping frameworks like Hibernate or Spring Persistence. 

2. These databases are very well supported, both by the open-source community and by many vendors that provide support for them. 

3. These databases are small and lightweight enough to containerize easily and deploy and update through the same GitOps mechanisms you use for your application code.

4. These databases are supported in SaaS versions from most or all of the hyperscalar public clouds.

https://kylegenebrown.medium.com/database-considerations-for-microservices-f575d5448203