WiFi itself is a great thing, but without proper data gathering and analysis it is not nearly as useful as it could be. In some sectors, such as hospitality, many visitors interact with you venue almost exclusively online. They book a room, use your WiFi network, then leave and review by posting their opinions on TripAdvisor, Yelp, or simply talking to their friends about what the enjoyed and what they did not.
In other ones, like retail, they hardly interact with you at all - they simply visit due to convenience, and are hardly concerned about your brand's identity or approach. That needs to change, especially if you expect them to create a bond with your company (and let's be honest, that's what all of us want).
The possibilities stretch much further than that. Gathering customer data is absolutely crucial for 21st-century-style marketing communication, where content, matching interest and consumer preferences are what most companies need to focus on in order to achieve effectiveness. It does make a difference whether your store's website add is being displayed on a desktop device or on mobile. To add on that, it actually matters what operating system, and even what software version they run, when it comes to your website being responsive.
The question we want to leave you here with is quite simple: do you actually know who your customers are, what they want, and how they communicate with you?