Zabbix by default updates configuration from the database every 60 seconds. That means whenever you change something in the configuration you need to wait at least 60 seconds for it to be reloaded by the server. This usually isn't a big problem, except when you created/edit maintenance which you want to be active instantly. A good example is when your deployment software creates a new maintenance before it continues with the deploy. Currently if you want to automate the whole process your deployment software needs to wait 60 seconds after creating the maintenance before it can continuing, so that the maintenance gets read by the server.
It would be great if the API exposed a new method configuration.reload which would instantly reload the configuration cache. This would make automating the creation of maintenance a lot faster, as well as making any changes which you want to work instantly.
Currently the Zabbix server supports running zabbix_server -R config_cache_reload which sends a signal to the server to reload the configuration cache, but on thing is to call an API, and one is to have SSH access to the Zabbix server with the correct permissions.