You're thinking only in terms of application. Types in the db save storage space, allow for better validation than plain strings, can be correlated cleanly with

You're thinking only in terms of application. Types in the db save storage space, allow for better validation than plain strings, can be correlated cleanly with other columns with the same type, etc. Yes, more drivers and libraries should support the more expansive data type list, but even just within the database itself there are multiple advantages.