This program was designed for Mac users who got tired of checking Facebook account updates using their default browser. App for Facebook sits on your Menu Bar from where you can access your news feed, send messages to your friends, and search for acquaintances with just a few clicks.
After you log in to your personal account, you can start sharing photos and links on your Facebook page, change your current status, manage your friend requests, etc. Basically, you will have everything done with just one click which is different from working with your browser for the aforementioned tasks.
Furthermore, the program comes with two display modes: one is similar to Facebook mobile view, the latter brings a larger window. Personally, I prefer the first display mode as it occupies a smaller portion from my desktop.
My only issue with this app is that you need to make an in-app purchase and upgrade to its Pro version in order to have access to all features. After paying a small fee, you will be able to adjust the opacity level of the main window, change its background color, enable notifications, etc.
As a conclusion, I'd say it's worth working with this program on your Mac as long as you want to skip using your default browser to check your Facebook account. App for Facebook is very simple to handle, uses a small number of CPU resources, and helps you keep track of everything is new on your Facebook feed.