Exploring components, what I reckon is that, the components are superset and Issues are sets and Subtasks are sub sets. Component sits at the top comprising of multiple issues of the same process and sub tasks are the smaller processes bred from Issues. Please correct me if I am wrong here.
Recommended Learning For You
Level up your skills with Atlassian learning
Learning Path
Get started with Jira Software
New to Jira Software? These short, self-paced courses will teach you what you need to know to get up and running quickly.
The Beginner's Guide to Agile in Jira
Learn what agile, kanban, and scrum are and how agile works in Jira Software.
Realizing the Power of Jira Reporting and Dashboards
Use out-of-the box reporting and dashboard capabilities to view and assess progress and bottlenecks within projects.