Dumbledore believes that Harry has just signaled to Lucius and the other Death Eaters that he will pay any price to save his friends.
Another way to interpret the events would be to say that Harry is willing to commit any act to save his friends as quickly and efficiently as possible. If Harry happens to have some money, he will use money. If he doesn’t have any money, he may use some hitherto unknown, yet unimaginably horrific power, which is so destructive that it is capable of frightening a Dementor. I suspect that at least a few Death Eaters on the Wizengamot might be thinking along these lines.
Scaring the Dementor may have saved his bacon. Blackmailing someone is a positive utility move. Blackmailing someone who seriously believes they can destroy hundreds of unkillable soul-eating monsters, and backs that up is a move with totally unknown utility, possibly very, very negative.
Another way to interpret the events would be to say that Harry is willing to commit any act to save his friends as quickly and efficiently as possible. If Harry happens to have some money, he will use money. If he doesn’t have any money, he may use some hitherto unknown, yet unimaginably horrific power, which is so destructive that it is capable of frightening a Dementor. I suspect that at least a few Death Eaters on the Wizengamot might be thinking along these lines.
Scaring the Dementor may have saved his bacon. Blackmailing someone is a positive utility move. Blackmailing someone who seriously believes they can destroy hundreds of unkillable soul-eating monsters, and backs that up is a move with totally unknown utility, possibly very, very negative.