I would love if GoTo would bring back the Ultra Low Usage line item for $6.95 as an option for overhead paging adaptors/loud ringer devices.
If it isn't allowed for desk phones anymore fine but...
You can avoid adding a user for paging if you use multicast paging. Just put a Viking or other paging adapter (Algo for example) that is capable of receiving multicast and connect that adapter to the input of your paging amp. Viking makes a unit that's all in one. It's not officially supported by GoTo but it does work and is very simple to set up.
Having something for a loud ringer is a more difficult but some of the Algo units also use multicast for ringing. It's less than ideal. You can get one low usage user and set it up with an ATA and the ATA to a Viking unit that will trigger ringing over your paging. That works very well but it's an extra expense for the customer because of the low usage user like you've mentioned.