While both a mobile responsive website and a mobile app can be seen and used on a mobile device, they are very different applications. A responsive website can be seen and used on a mobile device as long as there is a web browser available, but a mobile app must be downloaded and installed on a mobile device to be used.
A responsive website uses a cascading style sheet (CSS) to define how its real estate will be arranged on differently sized screens. The main goal here is to specifically dictate different designs based on the various devices showing the design. For example, a three-column grid on a desktop would automatically show as a single column on a mobile device.
The benefit of the full site is that you can make updates when needed and you don’t need to inform or request your audience make an update to the version of the application they have, like you do for an app.
Once downloaded, a remains on a smartphone and is best for frequent and repeated use.
An app is made to be a stand-alone product designed for a specific device (like an Android or Apple product) and is usually coded using Java or HTML for all the different versions needed to display and function beautifully on various devices.
Wearables are usually an extension of rather than a replacement for a person’s smartphone and tend to be personalized to the wearer. Because the hardware is fairly small, wearables currently tend to be less powerful than phones and tablets. The apps they run are either phone apps with only a handful of functions available or customized apps made just for the wearable that allow a limited number of use options.
People tend to use their wearables in short bursts of time to perform specific actions that can be done in seconds (rather than minutes). If something is going to take more than 10 to 20 seconds, more often than not the user will prefer using their phone.
But with more individuals using wearables and innovation driving sales, the ultimate goal for developers is to improve hardware, battery and overall functionality to the point where consumers have the ability to conduct “phone tasks” on their wearables instead.