If the email server is offline (and cronjob for emails is not enabled), a delay in using the web interface is seen:

if unable to place the email in the email server queue, then the connection to the server is down,

and hence no point to continue trying with the rest of the emails.

if ( !email_send( $t_email_data ) ) {
continue;
}

Instead of breaking out of the loop we continue through each email. As we take smtp server from the config, this means trying to make multiple connections to the same smtp server which is offline.