Well it’s as temporary or as permanent as you wish - it will remain until you change that line in the config file.
The config file allows you to lock values for certain settings - see your config-dist.php file for all the options. The usual advantage is that that file overrides the database settings, preventing them from being “messed about with”. That allows hosting providers or IT departments the ability to establish various setting without worrying about users/admins being able to change them. The disadvantage is that you can’t override them via the Moodle admin interface so it relies on a level of tech support that some people just don’t have. Whatever works best for your needs
The config file allows you to lock values for certain settings - see your config-dist.php file for all the options. The usual advantage is that that file overrides the database settings, preventing them from being “messed about with”. That allows hosting providers or IT departments the ability to establish various setting without worrying about users/admins being able to change them. The disadvantage is that you can’t override them via the Moodle admin interface so it relies on a level of tech support that some people just don’t have. Whatever works best for your needs