this is similar to what has recently been introduced to Disneyland California.
In Disneyland California they have the same Fastpass system as Disneyland Paris, ie the paper Fastpass which you get at the machines beside the rides.
This year they have introduced a paid way to also get Fastpasses. The free paper Fastpasses are still available, this paid way is in addition to the paper ones.
The paid Fastpass facility is called Maxpass. It costs $10 per day per person. It can only be bought once your park ticket is scanned. It is an extra paid service on the Disneyland App on your phone. Just like with the paper Fastpass, you can get as many as you like during the day.
As the free Wifi in Disneyland California is not park wide, you need to use data on your phone, which makes this facility useless for international visitors. I did not pay for Maxpass on my June 2018 visit but I still managed to get whatever Fastpasses I wanted and multiple Fastpasses throughout the day, the same as I have always done.
However from what I am reading on another forum and form my own experiences in Disneyland California a few weeks ago, it seems that American people are paying for it and using it..Americans seem to like the fact that you dont have to run around the park to the Fastpass machines beside the rides. They seem to like that you can just do everything on your phone through the App. They would rather pay $10 a day for the convenience.
With Maxpass you can get a Fastpass for a ride on your phone, You dont have to actually go to the machines. This means that while you are waiting in line for a ride, you can book a Fastpass for another ride. Also if you are in one park you can get a Fastpass for a ride in the other park. For example, if you are in California Adventures having a meal, you can go on your phone and book a Fastpass for Star Tours in the main park. There is also the facility to cancel a Fastpass.
Now that people have a digital version of a Fastpass on their phone, the CM's at the rides do not collect the paper Fastpasses any more. When you return to a ride now, you scan your phone OR you scan your park ticket if you have pulled a paper Fastpass. The paper Fastpasses are now just a receipt, so that you can keep track of your return time and when the next one is available.