Amazon thinks people will pay for Alexa?
I'll make a prediction: No they won't.
But this is, after all, the test -- right? "AI" has to generate revenue somewhere or its just a bunch of people playing with very expensive computers that use a lot of power -- twice, once to run them and then again for the A/C so they don't melt.
Remember that when this stuff first showed up as "customer service" went more-and-more toward automated response systems (which was, at first, "supervised" and in some cases still is, which is an easy "carry" from a human to a robot; you're none the wiser if its a chat window) the prediction was that basically everything would go this way.
It has, kind of -- but only in terms of the "initial" customer service line stuff. If its "which item are you returning?" then its pretty easy, but really not any different than the same interaction with a mouse on a keyboard when you get down to it.
What hasn't happened is widespread adoption of "digital assistant" stuff that is actually, well, worth something aka "Jarvis."
My prediction: Free works for the here and there, but a subscription will not unless it actually does useful things with near-100% reliability, and I don't believe either of those two metrics will be met.
This isn't like Adobe going to subscription software where they have a "hook" in that your 10,000 prior edited pictures suddenly become inaccessible if you don't pony up the next month's (or year's) fee. Now you have to get continuing and daily value -- which means it has to be timely, save you time or effort and be accurate or you're not going to pay.
Unlike a Starbucks coffee you can't drink this one.
My bet is that it fails.