Except if they had followed Vance’s original idea, and put distance between the Breen and Moll and L’ak (and maybe go somewhere in the galaxy that knows Breen medicine) maybe you delay the forces of the Breen primarch, have time to convince Moll and L’ak that you’ll protect them and won’t use them as bargaining chips, and you avoid all of the fuck ups of the third act. Burnham lied about having Moll in custody when they were trying to get her to calm down and come back to sick bay. What’s the difference between her lying about their whereabouts and Starfleet lying to the Breen about it, at least for a while, to attempt negotiation?
But the plot demands that Moll and L’ak be there so they can act like idiots, setting up the Breen joining the search for the super tech.
Also, does cloaking not work anymore? Both Discovery and Starfleet HQ had cloaking tech. Why not just jump away, cloak the ship, and use old-fashioned warp drive?