Efficiency is dependent on member’s ability to accept a payment, for international communities that might be more difficult and there isn’t a way through the discourse app directly already developed for that I’m aware of so perhaps that is what a new plugin/feature could help with.
If it’s a local community can just offer payment in cash, or using common apps like paypal/venmo. Also can just write and deliver or mail a check for anyone who still accepts checks and doesn’t want to loose a 2%+ fee to 3rd party. (venmo doesn’t charge that fee for personal transactions, but business account transactions do have fees and sales tax).
If members have their own business with other means of accepting a payment such as with stripe or other debit/credit card processor that can be better but then there are also fees with that.
Anyway it seems like one of the important parts of this discussion at a philosophical level is the impact financial gain incentive can have on individual community members as well as a community as a whole. Offering payments for individual post amount/quality may have more risk then a consistent salary method of payment. $10 a month is obviously not close to a living wage for anyone, that is just arbitrary amount that could represent someone being present and occasionally starting new topics or responding to other topics at a community site.