There might be some bickering about using it against Charlie in court, but Charlie explaining the business probably didn't do all that much that couldn't have been figured out from the records in the studio. I'm not sure they'd need it. They can use it against Sal, for sure.
It will be enormously useful for Hank Monroe explaining why he killed a cop in a police station and for Ramos and Janick to defend themselves to their bosses who are going to be asking what the hell is going on.
And it might be very useful in another way; Charlie Miler started that meeting thinking that loyalty would pay off in the long term, and that Riz was going to spring him/help him, and he can't think that any more. Neither can Sal. And now Schultz and Janick have Sal and Charlie to play off against each other. Neither deserves a plea deal, of course, but that situation just shifted and shifted big.
And the story that Samantha James is already covering suddenly went from story-of-the-week to story-of-the-year.