Yeah, I'd love to hear the explanation on this too. Not sure how it can be tech limitation when you could do it last year without an issue. The limitation should be on your PS4 available drive capacity...certainly not on the download process.
Yes, you can use a USB. Yes, there is a workaround. But why need to? This was a head scratcher and is inconvenient for the end user.
I hope they clarify why it was necessary.