AIP-158 page_size fewer than requested

[Bu3a3a]

Hi!

AIP-158 states:

The API may return fewer results than the number requested (including zero results), even if not at the end of the collection.

To me it seems weird to make N requests to get data. The most 'scary' thing is that number of empty or half-empty responses is unknown beforehand.

Could you explain, please:

1. In which cases returning fewer or zero results not at the end of a collection is possible and appropriate?
2. Doesn't it cause front-end issues? If it does, what approaches are common to prevent them?
3. Doesn't it cause unnecessary/excessive network load in some cases?

I'm trying to comprehend why it's so and how to painlessly work with this restriction. Sorry if the question is newbie. Any answers/links for reading are appreciated.