Ten years ago, I did some experiments building an "input lag measurement device" for touch screen devices with an Arduino. https://github.com/graup/feedback-delay-measurement
The research was related to QoE in cloud gaming. At that time, some Android devices had insane lag (125 ms+), whereas Apple devices were already consistently around 30ms. I assume this isn't a problem anymore nowadays.
Last time I checked (a few years ago), it was cheaper to send letters and small packages from South Korea to Germany than from Germany to Germany. The delay was also not that big (maybe 1-2 weeks instead of 3-5 days). I already envisioned an arbitrage business for this: a simple page where people upload their non-urgent letters as PDFs, and I just print and mail them from Korea.