nosql database is the norm these days and yet RDMBS databases like mysql, sqlite and sql-server are very much relevant too.

Most popular open source CMS and apps like wordpress, drupal, Magento, Craft CMS, etc. continue to use an RDBMS database rather than nosql one.

What kind of apps have you developed where nosql had come useful (and there was a better case or argument for using it against RDBMS for reasons)?

Do you think nosql databases are still suitable for traditional apps like ERP/CRM/FAS? Why and why not?