I think unsought incentives are unavoidable because they work to funnel human energy in ways that are not necessarily aligned with the target-customer-enduser-zappee’s conscious intention. Whether it would be considered “good” or not is open to negotiation on the free market of ideas, which, as a value assignment, is subjectively relative. Are the ways in which Duolingual learners’ habits get played through emotion good for them? Yes, in a utilitarian sense but no, in the broader Kantian sense of self ownership.