Why anacron does not call the crontab user files?

Why anacron does not call the crontab user files?

I want a special command to be lauched everyday, but dont want to put it in the /etc/cron.d/ because its a user specific user!
pg@pipoTower: ~$ crontab -l
# m h  dom mon dow   command
0 0 * * * updatedb -l 0 -o ~/.externalharddisk.db -U /var/autofs/removable/usbData
The crontab -e command which puts the file in /var/spool/cron/crontabs/userName
but dont know why its not called by anacron....
usr@Tower: ~/$ cat /etc/anacrontab
# /etc/anacrontab: configuration file for anacron

# See anacron(8) and anacrontab(5) for details.

SHELL=/bin/sh
PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin
HOME=/root
LOGNAME=root

# These replace cron's entries
1       5       cron.daily      run-parts --report /etc/cron.daily
7       10      cron.weekly     run-parts --report /etc/cron.weekly
@monthly        15      cron.monthly    run-parts --report /etc/cron.monthly