What is the difference between an in-app message and an inbox message?

An inbox message is plain text, whereas an in-app message can be populated by a CloudPage

An inbox message shows only one time to the user, where-as an in-app message keeps getting shown until its expiry date.

An inbox message only works on iOS, but in-app messages work on both iOS and Android

An inbox message is sent to an inbox that's part of user's mobile app, and stays in the user's inbox for a specified time, whereas an in-app message displays to the user only one time.