Are you talking about still cameras or TV cameras? I think that still cameras are fine but that TV cameras are a bit dangerous.
I do not see anything wrong with still cameras, though I think that photographers should not be allowed to click away (if their cameras make noise) while lawyers or witnesses are talking. I see nothing wrong with having pictures of the lawyers, witnesses and judges. (But I would not want the proceedings disrupted by flashes and clicks and stuff like that, so it depends on the technology.)
TV cameras are worse, in my opinion, because they encourage lawyers, judges, maybe even witnesses to show off for the camera rather than just going about what they are supposed to do.