It's the authors choice to set the price, and they do offer a free plan. For you maybe the value isn't there, but that doesn't mean a "GPT-4 wrapper" can't provide others value. And I give credit to the author for going with $30 instead of something silly like $6 because trying to build a business on $6/mo is a much harder than on $30/mo.
That's not at all improbable. And if you can't set things up so both minnows and whales are paying the price they are comfortable, its often a better business decision to dump the minnows and the overhead of supporting them and focus on the whales rather than having both, but paying minnow prices.
It is convenient to see a preview of the generated code without having to copy/paste it to your IDE and switch to the browser.
But I see it as mostly useful in the beginning when you are starting, or want to create standalone components. It would be great if it was implemented as a plugin to an IDE and could understand and modify an existing project.
By suggesting it's "mostly useful in the beginning" you are admitting that at some point they will copy+paste it to their project. So the convenience factor is a moot point.
I see the value, I just think that's an unrealistic price given the current features.