Their turnover is reduced. They must fire employees. They also pay less taxes - which offsets the taxes that casinos pay. Sometimes these businesses close down altogether. Anyone who visited Atlantic City or Gary, Indiana can testify to this.
Statistics show that casinos prefer to employ non-local people.
They employ foreigners. If this is not possible, they will try to employ people from Bitola in Skopje - and vice versa. This is intended to prevent collusions and conspiracies between the staff and the gamblers. So, we cannot even say that a casino generates employment for the inhabitants of a city whose infrastructure it uses. There are some alarming statistics.