While most of the applications built with AppSheet is focusing on the usage and functions within an organization or team, many app creators (including myself) are also pushing the limits and exploring more possibilities to build customer-facing applications with AppSheet.
When creating an app for customers, I find it very useful for the Onboarding View to be the first view of the end-users (customers) to showcase your brand, or presenting the “Getting Started” or “How To Use” part of your app, or for other purposes.
The Onboarding View could also become “the ads section” of your app if you want (or need) to. Thus creating an impression for the end-users to showcase your ads before they can actually access the functions of your app.
In this case, putting an option to disable the close button (X) on the top right corner of the Onboarding View can be a great tool or option for the app creators to make sure that all the slides in the Onboarding View will make an impression (or appearance) to the app users before they can access the app.