Power Automate is not a necessary tool.
However, if you plan to use Triggers, Creating ticket via email, and SLA then Power Automate is required
Requires Power Automate Per-user-plan license for 1 user only (This is the user who will have the workflow running in their context).
If you have MS365 E3 or E5 license, you should check if the Power Automate is included in your license.