The BIS library is free and fully accessible for all users. Any content (materials or meshes) from the open part of the library can be downloaded by any user without any restrictions. So why do you need a pro- account?
At first, this is a way to support the project. Like any other free project, BIS needs the user’s support. However, the BIS pro- account is not only a status attachment. The pro-status does not provide any additional content, but it allows you to make your pipeline with BIS more convenient.
Pro-account users have the following advantages: