This is just a matter of what we prefer and what we want and like to use.
I myself prefer to use the web version rather than the app since I think that's quite easy to use and accessible to me and I think many will think similar.
My friends are using the web to so I believe there are more web browser version user rather than the app since if I'm not mistaken the web version come out first so it gather more user after the app.
There are actual web users because the features are easy to navigate with the use of your personal computer or laptops. While the app version, this is for convenience whenever you are away from your PC/laptop.