You are right, this is an open-core model. The PRO features are proprietary and, to be precise, they are actually modules that integrate into the core of the solution. In addition to these features, the PRO version gives you access to technical support.
We completely agree with you that BunkerWeb can be used by everyone to make the web more secure. We sincerely believe that the features offered in the community version contribute significantly to this goal. Thank you for your feedback.
Performance will indeed decrease compared to a web server without security features. However, this largely depends on the BunkerWeb features you choose to enable.