If you live somewhere that it's hard to hail a cab, Uber cars get there more quickly. They cost more per ride, but it's worth it if you measure time in dollars per minute.
I didn't really see any "hidden cost" there except for the "time is money" argument. By that measure, I could include the hidden cost of going to places with long lines, talking to long-winded people, or anything else.
Uber has a nice service, and I've used them here in New York when cabs are changing shifts and scarce, and I have to be somewhere right now. They are much, much more expensive than cabs, and even more expensive than a call-ahead car service. That's why I only use them in very specific situations. They're convenient and expensive. That's okay. But a lot of charts and hundreds of words to say "time is money" is a rather ironic way to spend one's time.