I first wrote about this problem over a year ago and the problem is just as bad today, but the designers of these apps are getting better. The issue is that these apps are really careful to comply with the rules of the App Store, so ultimately it comes down to a decision on whether the subscription is value for money, which puts Apple in a really tricky position.
Is $150 a year too much for a QR code scanner app? Yes, clearly. But where does that line lie? Is $20 a year too much? Well, I'd say yes since the built in camera app does it for free, but I'd not want an app removed from the store for that. It's a really slippery slope.