Libraries are great. Quick to get started, quick to keep using, great for common usecases.
Now, if you want to build something custom, something that delights and astounds, something that makes your users love you ... You're gonna have to understand how combining React and D3 works under the hood. Whether you use a library or not.
A rule of thumb you can use is to consider how custom you want to make your visualization. The more customizations, the more likely you are to benefit from rolling your own.
Or if you've had a lot of practice with rolling your own and it's literally easier than learning a library.
If you have to customize an existing library, or build your own for the team, that's what we're here for today 😃