[Observium] Cron (silly) question

Why you mention to use cron files ? On an EL system (Centos 6.5 specifically) I just use crontab -e and it works fine for weeks now:

[root@devil ~]# crontab -u root -l 33 */6 * * * /opt/observium/discovery.php -h all >> /dev/null 2>&1 */5 * * * * /opt/observium/discovery.php -h new >> /dev/null 2>&1 */5 * * * * /opt/observium/poller-wrapper.py 5 >> /dev/null 2>&1

[root@devil ~]#

(just wondering if there is a specific reason...)