Yes, it would require the end user have permission to use App resources.
Share an App in PowerApps
Share app resources
In addition to use a flow, you may consider take use of Office 365 Outlook connection to send the Email:
Office 365 outlook
For delveloper view, at least currently it is not possible to customize the flow usage under PowerApps, you may consider submit this as an idea under PowerApps idea forum:
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Features releasing from October 2019 through March 2020