App subscriptions are often seen as “renting” the software. One can use it only while paying for it. This puts users at the mercy of the developer:
The rates are increasing? — Keep paying or lose access.
Support does not respond? — Keep paying or lose access.
No useful features for months? — Keep paying or lose access.
You want to cancel? — Forget about the money already spent.
No wonder users hate subscriptions.
On the other side, improving the app and providing support is a regular work with no end date. A single purchase won’t do — continuous work requires continuous revenue.
The new update brings quite a few improvements: new app icon(s), improved backup, detailed file locations, Japanese translation, and free trial for premium subscription.