Inner-Platform Effect

> While this entity-attribute-value model enables the developer to break out from the structure imposed by an SQL database, it loses out on all the benefits,[1] since all of the work that could be done efficiently by the RDBMS is forced onto the application instead. Queries become much more convoluted,[2] the indexes and query optimizer can no longer work effectively, and data validity constraints are not enforced. Performance and maintainability can be extremely poor.

This is only true if you try to do this for all of your data.

I've used key-value tables loads of times, it's convenient for storing things like global configuration.

What else can you do? Make a table that has every configuration value as a separate column and populate it with only a single row? That seems absurd and worse.

I mean with things like webbrowsers it's so a group of people can have a similar experience regardless of which operating system they are on.