Convenience, speed, and technical difficulty (for the typical person, not HN reader). Definitely, I've faced this problem. My photo and video library on Google Photos is now much larger than the free space I have on any device. The hassle of downloading in chunks, just to re-upload (and heaven help anyone on an ISP with data caps) is huge. It's also probably very slow - consider the bandwidth between an Apple and a Google server - most likely in the 10Gbps range? Compare that with an average person doing 50Mbps down and then 8Mbps up. For a 500GB library that takes _hours_.
As I read it, the amount they were spending on the ads themselves was more than the converted revenue from ad clicks. While the decline was probably (guessing) not linear, spending more on ads led to less than proportionally more revenue. If that had happened I can imagine calling that negative ROI.
TLDR; USB3.0 high speed signals when not properly shielded can cause RF interference with RF devices operating under 5Ghz due to the broadband nature of the signal.