So emergent properties can be self-causal. The move to saying that qualia affect behaviour has many implications. In the first place it allows an evolutionary reason for consciousness, if indeed qualia aid survival beyond nonconscious processes. Second, qualia should affect evolution. This suggests, surely, that we might find evidence of qualia perhaps in ancient paths of evolutionary development.
Biologists explain behaviour without reference to consciousness.
Some psychologists explain human behaviour in terms that include likes and dislikes, with the underlying assumption that hedonism has a large part to play. These psychologists at least implicitly assume that qualia are causal. This fits common sense. A complication here is that immediate hedonism is very commonly tempered by long-term planning and expectations. Thus a poor student will suffer now to gain degrees of freedom for later rewards.