I don’t know about Google Wallet, but for iOS Wallet, it is not possible to create a new entry there yourself as a normal user.
It has to be signed with a $99/yr certificate, so this thing does the signing for you. The utility is that whatever you created now lives with the rest of the passes in one place.
So yeah, in Google Wallet you can just add the loyalty card like that (scan the qr/bat ode or type the number), and then have it synchronised to your account (to have it available on your other phone for example).
Sure, not every kind of the pass can be added like this (not movie tickets or boarding passes), but all that matters.
