That means: it's conceptually overloaded for doing quick-and-dirty conventional charts, where you just want to plug in a few parameters and have it "just work" - but excellent once you need to customize and make it work with your specific requirements.
That it has the concepts, and a clear notion of them, is the critical difference. Most libraries, most of the time, don't add new concepts, they just have a premade black box of features and functions. Sometimes you want a premade black box, but often you want to open up the box shortly afterwards, and that creates the inevitable trend towards either remaking it as your own box, or being one of hundreds of people who gradually grow it into a monstrosity that does everything.
But a library that is concept-focused doesn't have to get that much bigger: it's just another kind of interface, like a programming language or an operating system, and that puts it on a more sustainable track.
That means: it's conceptually overloaded for doing quick-and-dirty conventional charts, where you just want to plug in a few parameters and have it "just work" - but excellent once you need to customize and make it work with your specific requirements.
That it has the concepts, and a clear notion of them, is the critical difference. Most libraries, most of the time, don't add new concepts, they just have a premade black box of features and functions. Sometimes you want a premade black box, but often you want to open up the box shortly afterwards, and that creates the inevitable trend towards either remaking it as your own box, or being one of hundreds of people who gradually grow it into a monstrosity that does everything.
But a library that is concept-focused doesn't have to get that much bigger: it's just another kind of interface, like a programming language or an operating system, and that puts it on a more sustainable track.