> Since Proof of Age Attestations are designed for single use, the system must support the issuance of attestations in batches. It is recommended that each batch consist of thirty (30) attestations.

It sounds like application would request batch of time-limited proofs from government server. Proofs gets burned after single use. Whether or not you've used any, app just requests another batch at a set interval (e.g. 30 once a month). So you're rate limited on the backend.

Edit: seems like issuing proofs is not limited to the government, e.g. banks you're client of also can supply you with proofs? (if they want to partake for some reason). I guess that would multiply numbers of proof available to you.