Why does it say that Scrooge is left with an improved opinion of himself, following the visit from the charity collectors?

Scrooge asks the charity collectors if there are no prisoners and if the Union Workhouses are still in operation. Scrooge was a money-lender, so there would have been many people in his debt that he allowed to work in the Union Workhouses instead of going to jail for not paying back; since they're still in operation, presumably people are still working there instead of sitting in jail.