Hi @Anonymous ,
In addition to @OliverRodrigues answer. Just would like to add my insights.
With the recent release wave with portal you can also create custom components which is a fab feature.
Things that can not be achievable with configuration:
1. Capturing success and failure flags from Power Automate and responding back to the powerapps portal.
2. No inbuilt functionality for offline storage yet.
3. Forms look and feel customization -needs advanced CSS
4. Couldnt upgrade to bootstrap 4 or advanced.
I am adding the wonderful diagram from one of our MVP and overview of the Power Apps Portal current capability for your reference

Hope it helps.
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