Visible light communications are the offspring of well studied infrared wireless systems and can form a promising enhancement of future illumination infrastructures with communication functionalities. However, supporting data rates of hundreds of megabits per second cannot come for free with respect to lighting system costs. This article addresses the limitations that lighting requirements impose on VLC systems in terms of modulation bandwidth, received power, and cost constraints. The achievable data rates of joint VLC and illumination systems are discussed, and examples of possible applications are provided.