Question

what is the purpose of grouping objects​

Answer 1

Grouping Objects. The Group command groups two or more individual objects (including text and symbols) together. The group of objects is then treated as a single object. For example, grouped objects can be moved to a different layer in one move.

Answer 2

By grouing several objects together, we can treat them as a single one. After this, we can bring about changes to all of the objects in one go, instead of doing it separately for each individual one.