This is a good point. There are a lot of reasons you might get a small boost of productivity after starting a new therapy approach.
7 days isn't enough time for the vast majority of people to know whether the app is doing anything at all for them.
"Spend a week playing with something new and interesting that you might just hyperfocus on, and then impulsively pay us for a year's access because this time you won't lose interest in two months" feels laser-targeted to prey on ADHD behaviors.
Basically the model here is like a gym, where people buy things that they don’t use as much as the price implies or is simply ineffective.
Given that the customers are executive function impaired, seems shady.