What is the most useless app that you have seen being given as a subscription?
For me, I tried a 'minimalist' launcher app for Android that had a 7 day trial or something and they had a yearly subscription based model for it. I was aghast. I would literally expect the app to blow my mind and do everything one can assume to go that way. In a world, where Nova Launcher (Yes, I know it has been acquired by Branch folks but it still is a sturdy one) or Niagara exist plus many alternatives including minimalist ones on F Droid, the dev must be releasing revolutionary stuff to factor in a subscription service.
Second, is a controversial choice, since it's free tier is quite good and people like it so much. But, Pocketcasts. I checked it's yearly price the other day, and boy, in my country, I can subscribe to Google Play Pass, YouTube Premium and Spotify and still have money left before I hit the ceiling what Pocketcasts is asking for paid upgrade.
Also, what are your views on one time purchase vs subscriptions? Personally, I find it much easier to purchase, if it's good enough even if it was piratable, something if it is a one time purchase rather than repetitive.
I don't want or need continuous updates.
I want to buy something and have it be left alone without trying to steal more money from me for the thing I already bought.
The only possible valid excuse for a subscription to software is services that cannot possibly exist without meaningful spending on server infrastructure. If that's cloud storage as the core of the purchase of the app, computations that are literally impossible to do locally or rely on data that's expensive to maintain, a subscription is legitimate.
If it's anything else it's shitty and you're a shitty person for doing it. Sell actual upgrades when they're actually upgrades, without stealing access to what people bought. It's the only acceptable model.