I wrote a bit about this from the perspective of a data scientist here: https://www.robinlinacre.com/demystifying_arrow/

I cover some of the use cases, but more importantly try and explain how it all fits together, justifying why - as another commenters has said - it's the most important thing happening in the data ecosystem right now.

I wrote it because i'd heard a lot about Arrow, and even used it quite a lot, but realised I hadn't really understood what it was!