In many environments its generally so that there are multiple servers with the same applications but where some things are slightly different.
In order to prevent duplication items could be combined to use macro data (e.g. in IIS application pool monitoring where the application pool names differ per server or stuff like SSL certificate monitoring using site hostnames running on the server).

To monitor this, items and triggers need to be created.
If there are more of the same (e.g. many application pools / ssl sites) its quite annoying to have to create them all with just one minor change ($SSL_SITE1, $SSL_SITE2.... etc) especially if you have to modify them all to act differently.

It would be better if this could be templated somehow, where one trigger/item can be duplicated internally with other parameters.
This would prevent duplication & repetition and should make it easier to maintain.

(Feel free to fix the summary, I couldn't summarize this properly into one sentence)