For instance, for many simple needs MySQL is simpler than Postgres, with similar performance and consistency.
* No need for a connection pool, while many use cases with Postgres require PgBouncer and Co.
* Easy sort (and basic search) of multilingual text, because MySQL has case insensitive UTF8 collations.
* No need to VACUUM, which can be a hard problem (it was, the last time I used Postgres).
For full text search, I once worked on a project that considered several alternatives for this, including Postgres. Manticore Search was finally chosen because it was more performant, with better search results.