If it works, then that’s not a bad price at all. ADHD attentional issues will suck orders of magnitude more money out of your life if left untreated in some people.
If it works. If it doesn't, then that's just another $99/month money hole that people with ADHD have a particular difficulty digging themselves out of - subscriptions are like a kryptonite to them.
Not really - cancellation being objectively as easy as signing up is still much harder to actually do for people with ADHD.
Signing up is something exciting and fun and something such person may do impulsively in a moment of weakness. Cancelling is boring and scary (what if dark patterns?) and a chore you don't look forward to, but rather try to not forget. It's not positively rewarding, but merely stops a penalty.
This might seem like an exaggerated difference, but it actually hits the exact points that are affected by executive dysfunction.