Is restart after phishing site update necessary?

[pidydx]

From /etc/MailScanner/defaults

# Restart MailScanner after Update Safe/Bad Phishing sites
#
# Restart MailScanner after update of the Safe/Bad Phishing sites files.
# This is disabled by default.
#
# This is executed during the DAILY cron option.  0 = off, 1 = on
#

ms_cron_ps_restart=0

This being disabled by default suggests that it is not necessary to restart anything for updates to take effect, but this option existing suggests there is some reason why you would want to. I was unable to find anything in the documentation describing the purpose of a restart here.