Chose payment methods

[s-tikhomirov]

The incentivization protocol is agnostic to payment methods. A payment method should generally have the following properties:

• wide distribution;
• good liquidity;
• low latency;
• good privacy;
• high security.

Let's list all decentralized payment options:

• ETH;
• a token on Ethereum (ERC20);
• a token on another EVM-based blockchain or a rollup;
• a token on a non-EVM blockchain (such as BTC / Lightning).

Note also that there may be different market models that may motivate the choice of the payment method. One model assumes that each client pays for its own requests. Another model includes (centralized?) entities (i.e., developers of Waku-based apps) that pay for their users in bulk. It is then up to such entities to limit their users' bandwidth consumption to prevent overuse.

We also note that:

• eventually the protocol may support multiple payment methods;
• however, the PoC version should be simple, which likely means supporting just one payment method;
• if the initially supported payment method is an ERC-20 token, it should be easy to add other ERC-20 tokens later, including a potential WAKU token.

[fryorcraken]

Do note that the payment methods needs to work on resource-restricted devices such as mobile and browser.