Time Out did an investigation that suggests maybe they really are legitimate businesses making a profit, and not money laundering fronts as commonly suggested:

Time Out did an investigation that suggests maybe they really are legitimate businesses making a profit, and not money laundering fronts as commonly suggested: https://www.timeout.com/london/shopping/why-is-central-london-suddenly-full-of-american-sweetshops https://www.timeout.com/london/shopping/why-is-central-londo... But I dunno, the sheer number still seems kinda sus.