The ability to link words with address or geolocation. It's free and easy to use, although it can be difficult to learn some of the rules that govern how to set up your keywords. What3words works particularly well with businesses in retail and hospitality, where you can have specific categories of products or services (such as'shoes' or 'coffee') in order to describe location. This is especially useful when working in multiple countries, and using different local languages. The ease to use, how accurate it can be (or not) in comparison with other mapping services out there! Also that I like everything about this product - their customer support team are amazing too!! Nothing at all really so far as i'm aware but if you have any questions feel free send them my way :) highly recommended- we're using 3 words instead now which has saved us A LOT OF TIME.