Dr Miller1 raises issues reviewed elsewhere by Draelos with comments by Gold and Harris.2
They highlight other aspects of physician product sales such as the responsibility to dispense knowledgeably, the dangers of misrepresentation, profits and revenue, convenience for patients, value and availability, quality control, continuity of care, lower prices, and the advantages of providing patients with expert purveyors of products.
Gormley DE. There Is Nothing Wrong With Dermatologists Selling Products to Patients!. Arch Dermatol. 1999;135(7):765-766. doi:10.1001/archderm.135.7.765