My wife has Alzheimer's and this looks like it is perfect for this use case. She can't cope with too many options/choices and only needs/wants to make phone calls, texts and take picture, then look at the pictures she has taken. Four simple things. I have tried many phones and apps (mostly Android) with "assistive" technologies and NONE of them truly lock the phone into a known state that she can't accidently change or require too many options on screen. Having gone through several phones in the last year to 18 months, this is the only thing I have seen that locks down the home screen, yet allows me to make changes if I need to. While this feature really requires an administrator, it is the best I have seen for people with cognitive challenges. While I don't know the developers intent or motivation, this feature feels like someone on the team was dealing with a family member with cognitive challenges or just has a lot of empathy. I don't believe this feature is intended for someone that wants to make their "smart" phone into a "dumb" phone.
My only issue is that when the iPhone I bought her didn't work out I took it over and got an Apple watch to go with it and paired an Apple watch with cellular for her. So, I will need to buy yet another phone for her......