Hypernap may be a native app, but it's certainly not beautiful or fully featured. It uses the most basic interface elements thrown together in a messy soup. I have immense respect for people who manage to develop native apps, but when the interface looks like it was implemented as someone's very first experiment in XCode... well, there's a reason you don't pay much.
I don't understand why developers throw their arms in the air over pricing. Try out the app; if it has everything you will ever need out of such a tool and it greatly improves your productivity every single day... a one-time $50 payment is nothing. It's the cost of going out for dinner one evening.
It doesn't have to be 12x better. It only has to save you $45 worth of time more than a $5 alternative, or $50 more than a free alternative. Most engineers are paid on the order of $30-$150/hour, depending on whether full-time, contractor, level of experience, etc. So, it has to save about 1.5 hours over the alternatives to be worth the price.
I don't know if it does that, as I've never used it, and don't use macOS.
There are other things it could save instead of or in addition to time: Hassle, maybe it doesn't have any external dependencies or complicated setup; stress, maybe it works reliably while others are buggy and unreliable; etc.
Again, I don't know. And, I tend to choose OSS solutions, even when it costs me more time/hassle/stress. But, there's a number of reasons one might choose a more expensive tool that does roughly the same job as lower cost alternatives, and it might be the right economic decision to do so.
I don't understand why developers throw their arms in the air over pricing. Try out the app; if it has everything you will ever need out of such a tool and it greatly improves your productivity every single day... a one-time $50 payment is nothing. It's the cost of going out for dinner one evening.