Need force immediately (1-2 minutes) auto-execute poll items/discovery rules after link template (to host). Now check rules will execute after Update interval timeout. When update interval is big we can detect template (or host configuration) error only after this big timeouts when see that rule don't work.
For example: we need gather snmp hostname only once at day. ifDescr once at hour. ICMP Ping (host alive?) - every minute. We make typo in snmp community (or do not enable snmp on host) and will detect it only after hour, when ifDescr not collected.
We can temprorary set small update interval to check template, but this template can be linked to 1000 hosts in production and zabbix poller overloaded. Templates force is "do all automatically".Therefore template need do first poll immediately and show to user/admin that "host is monitored now"