One of the big reasons there are no cameras is because they fear cameras would lead to performing for the public instead of argument focused on the law.
We actually don't need to see these hearings. Why would we? These aren't our elected officials, that's the legislative branch.
The Supreme Court issues it's rulings in public, and only those rulings really matter. It really doesn't matter what happens in these arguments because only the rulings have effect, and the rulings are based on a ton of things that have nothing to do with these arguments anyway.
I'd even say they should stop releasing audio of the arguments, or put them on a year delay or something like that. All too often we hear folks in these events seem to start making political speeches when that's not how this works.