Especially for those of us with no coding background, who can’t just build/edit an app.
For example, I like using Gadgetbridge to replace my fitness tracker app: https://gadgetbridge.org/
It’s not nearly as full-featured as a regular fitness app, but it literally can’t connect to the internet so there’s no way anyone can get my health info.
Well, I sure do purchase paper (and ink) but, unlike with stuff I would subscribe to, even if I would stop buying any more paper today I would keep a full and unlimited access to the one I already purchased, for as long as I fancy, at no extra-cost (1). Try that with a subscription, my young fellow ;)
1: the same with purchased films, series, music, licenses, books, and so on… Stuff I see no valid reason to keep subscribing to (I used to subscribe to many services), and enough good reasons to not keep subscribing to them.