One of the most critical issues with High Fidelity as a platform right now is that of friction.
Average users aren't going to want to do the multi-level abstraction of buying Ethereum, then buying the stablecoin (in a bank session), and then actually purchasing their content.
Critical to reducing this friction is a secure payment integration that will allow users to add money into the economy.
I propose using a third party payment processor; significant research would be required to determine the best option. https://www.carbon.money/ is an interesting possibility, as it is specifically designed for conversion between credit cards/apple pay/etc and stablecoins or other crypto.
The direct conversion to stablecoin also avoids significant tax implications of dealing with crypto like Ethereum.