I can't speak to the technical details, but form a user perspective, I'm able to reload the card from my iPhone and use it immediately, there is no loading "wait period". There's custom fare zones with different prices and multiple operators (Tokyo Subway, Toei Subway, JR East, and compatible with every transit agency in the country). When I enter the station, my Apple Wallet gives me a notification "trip in progress" and when I exit, I see the charges on the screen on the machine and on my phone. This all happens in less than 1 second (they literally advertise it on the reader, that IC is sub 1 second lol). Not to mention the card also work in many convenience stores, fast food restaurants, processing transactions in a country of 100 million plus.
I recognize technical challenges, but system like Presto definitely have a design and execution problem. It is impossible that a transit system with a fixed fare is more technically challenging than these foreign systems like Tokyo, Hong Kong, London, etc. They picked a terrible contractor (Accenture) instead of a proven system like Cubic then kept complaining about how it's just such a complicated system.