What horrible advice. Stop telling people to work harder without compensation. This isn't simply a matter of choice, it hurts the collective workforce. This isn't a charity, this is our livelihoods!
But it's always listed as something like "Premium Features" or "Monthly Subscription." Those descriptions don't tell what I'm getting. So then it's usually download the app, try to figure out which are the premium features and which are baked into the app. It's a mess. And I get it, it's not really the dev's fault, but the system is completely broken.