WordPress.org

Do I really need cron to use this plugin?

No.

If you are unable to schedule cron jobs, you may instead uncomment the very last line of the plugin (the one with 'wp_head' and 'update'). That will make the plugin look for posts on page loads, but only as often as specified in the update interval configuration. This is not the recommend method, as it slows down page loads for (some) visitors. Also, you likely need cron to run Venus itself anyway...