Q about Faust/CCRMA 2020 slides

As found here:

In the faustsynth example, all parameters include [hidden] except for the ADSR controls. There’s no mention in the slides of the use of “[hidden]” although it seems obvious from context. I’ve used Faust before on several other platforms and hadn’t come across [hidden] because it doesn’t make sense there.

So, are the ADSR controls NOT [hidden] for a specific reason?