With a web application, you will either have to type in the URL every time you wish to use the sportsbook, or keep it saved as a bookmark in the history of your preferred browser. With this, the app can be opened with a simple touch of the screen, and the general loading time and data usage will be faster and far more efficient than the online web application. This is largely due to the fact that the betting app would have been specially developed and optimized to work with the corresponding device. In almost every case, the fully downloadable native app of a given betting platform will be far more user-friendly than the online web application.
In this day an age, a betting operator should be offering a native app in order to make your life easier. With an online web application, the sportsbook is powered by the web browser. The main clear difference between a native sports betting app and a web application is that native apps require the user to download and install onto their device.
If you are using an older phone this could be trickier. A relatively recently updated operating system is usually more than adequate, whether you are using iOS or Android. Check the minimum download requirements of the app.