Could that be used to establish a specific base type for the array? And would the max. cardinality remain when used with set operations (union)?
Or could that be used as a test of “emptiness” for other arrays?

This picture misses the point. This isn't how anyone experiences becoming a developer - at least I hope they don't.
Where's the early awe of "making the computer do what I want" and the delight of seing great architecture in process?
It's like a box of crayons without and idea for a picture.

Captain Future - The Comet

Nope.

It's pretty clear that the "community" party moved on.
SAP is not home for their own user/dev community (and hasn't been for a long time).

Like a restaurant that was "the place" once SCN is now just a shadow of what it used to be.
Even if there's no new "the place" yet, you'd not return to it.

This reads as if there was ongoing internal training/education on how to use newish products in “the real world”. What consulting org would do something expensive like that?

Thanks! My thoughts exactly when I figured this out.