If you make a lot of purchases from the Mac App Store, your Purchased tab can get very unwieldy.
The Purchased tab in the Mac App Store shows you all the apps you've downloaded, free and paid. If you find the Purchased tab hard to navigate due to the sheer amount of apps you have downloaded, you can hide apps you may not need to see a record of, such as apps you never uninstall and always have running on your Mac. Or maybe you have young children using your Mac that you don't want accessing certain apps. Whatever the reason may be, hiding and unhiding Mac App Store purchases is easy.