Gambling is not going to help the economy to get recover unless it is a country where people from other countries gambles a lot than their own citizen and there are only few places in this world fits into such criteria and they have enough casinos and also facing lot of restrictions while running their casinos.
Casinos also offers job to people, after this pandemic there will be a lot of people racing to find a job and one of the places to reopen are these casinos that will be needing employees. These casinos don't just need people for the tqble, the bar and so on but also these places offers rooms and some venues too.