What is the difference between Item template and User item Type in PIM

When user creates Item from UI via Create Item task > Enter the Master Org and Item Class > Select the Template… user item type is getting defaulted same as the value that is selected in Template.

It is same behavior when item is created using Items Version 2 REST API. Whenever I am passing value in Template, same value is getting defaulted in user Item Type. In that case why do we need to different attributes in REST API as “Template" & "UserItemTypeValue".