The most important and essential quality of 'successful currency' is


#1

"The essential quality of successful money, through time, was not who issued it—or even how portable or durable it was—but rather the number of people willing to use it. "

(Quoted from Digital Gold).

I wanted to post this quote out as I think it focuses on a key aspect - total users (and thus value to those users) really, ultimately will determine the success of Ada as a currency at least.
Whether those ‘users’ are a bevy of dApps with smart contracts and ICO’s built on Cardano platform, or straight out currency use across the world, or both, I think it’s correct that success will be driven proportionate to total users.

Note that in an interview I watched today with Charles, he mentioned that it’s possible that they could create a value stable currency on top of Cardano for everyday use.
I think this would resolve the dliemma that Ada holders want the value to go up, but if you are holding a currency that keeps going up, you don’t want to use it to purchase things (and end up with something like BTC $100Million pizzas…).
Thus, Ada would be like shares in the Cardano platform, and ‘stable currency’ would be the daily use case with merchants.
Might be an ingenious resolution.