SCOTUS somewhat famously only allows audio recordings of proceedings.
https://www.supremecourt.gov/oral_arguments/argument_audio/2...
https://www.theatlantic.com/national/archive/2013/03/case-al...
https://www.supremecourt.gov/oral_arguments/argument_audio/2...
https://www.theatlantic.com/national/archive/2013/03/case-al...
e.g. If an organization/individual has ulterior motives (of fears) for testifying in a case other than the limited outcome of the legal question, it has the ability to sway their testimony.