A shorter way to automatically update WordPress?

If you have this statement (by default) in your wp-config file

define( 'WP_AUTO_UPDATE_CORE', true );

Then WP core files are automatically updated for you. This assumes that you have traffic to your site (if nobody ever visits your site, the updates won’t happen.)

So your solution is actually causing more work by the server, and is sort of redundant and repetitive. By default WP will check for core updates all on it’s own.