The protocol tokens ($PUSH) are designed to incentivize continued adoption cycle for the EPNS protocol. This is achieved by ensuring incentives for all the users involved by rewarding or encouraging them through incentives and penalty, their continued involvement is seen to be necessary for the growth and adoption of the protocol and to achieve the vision of becoming web3 notification standard.
Any dApp / protocol / services that want to send notifications. These are envisioned to be direct service owners (like AAVE, Compound, Cryptokitties, etc) or third party vendors who can build on behalf of these services.
People who want to receive notifications as that is beneficial for them.
Wallets / Infra Services
Wallets / other infrastructure building on top of protocol that
enables users to receive notifications through their centralized or decentralized solution (mobile app, web browser, user wallets like metamask, trust, etc). Includes the EPNS infra which does delivery.
People who hold tokens and define the rules between the above 3 players.