Why did al Capone wash and iron peoples shirts in al Capone does my shirts?

In "Al Capone Does My Shirts," the protagonist, Moose Flanagan, explains that Al Capone's involvement in washing and ironing shirts serves as a means of income for the family and a way to gain favor with the infamous gangster. Moose's family runs a laundry service on Alcatraz Island, where Capone is incarcerated. This connection reflects the blending of everyday life with the extraordinary presence of a notorious figure, highlighting the impact of crime and celebrity on ordinary families during that era.